Repository: shapesecurity/unminify Branch: main Commit: 1a000607c53c Files: 51 Total size: 111.1 KB Directory structure: gitextract_dhkidt2p/ ├── .eslintrc.js ├── .github/ │ └── workflows/ │ └── check.yml ├── .gitignore ├── LICENSE ├── README.md ├── bin/ │ └── cli.js ├── package.json ├── src/ │ ├── cli.js │ ├── helpers/ │ │ ├── codegen.js │ │ ├── fn-contains-weirdness.js │ │ ├── inlinable.js │ │ └── parents.js │ ├── index.js │ ├── safety-levels.js │ └── transforms/ │ ├── safe/ │ │ ├── cleanup-with-state.js │ │ └── cleanup.js │ ├── unsafe/ │ │ └── remove-unused.js │ └── wildly-unsafe/ │ ├── inline.js │ └── partial-evaluate.js └── test/ ├── snapshots-in/ │ ├── computed-member-to-static.js │ ├── expand-expression-statement.js │ ├── expand-multiple-decl.js │ ├── expand-sequence.js │ ├── hoist-fns.js │ ├── if-and-seq.js │ ├── if-not.js │ ├── indexing.js │ ├── inline-arguments.js │ ├── inline-called-once.js │ ├── inline-constant-object-property.js │ ├── inline-function-as-conditional.js │ ├── inline-iife.js │ ├── inline-trivial-function.js │ ├── make-blocks.js │ ├── negate.js │ ├── no-trailing-return-void.js │ ├── partial-evaluate.js │ ├── remove-empty-statements.js │ ├── remove-empty-try.js │ ├── remove-unused-vars.js │ ├── return-and.js │ ├── return-conditional.js │ ├── return-void.js │ ├── shorthand-if.js │ ├── spread-block.js │ ├── statement-position-negation.js │ ├── un-yoda.js │ └── unhoist-var-decls.js ├── snapshots-out/ │ └── test/ │ ├── snapshots.js.md │ └── snapshots.js.snap └── snapshots.js ================================================ FILE CONTENTS ================================================ ================================================ FILE: .eslintrc.js ================================================ module.exports = { extends: 'eslint:recommended', env: { es6: true, node: true, browser: false, }, parserOptions: { ecmaVersion: 2020, sourceType: 'module', }, rules: { 'arrow-parens': ['error', 'as-needed'], 'array-bracket-spacing': ['error', 'never'], 'brace-style': ['error', '1tbs'], 'camelcase': 'error', 'comma-dangle': ['error', 'always-multiline'], 'comma-spacing': ['error', { before: false, after: true }], 'comma-style': ['error', 'last'], 'computed-property-spacing': ['error', 'never'], 'consistent-return': 'error', 'consistent-this': ['error', 'self'], 'curly': ['error', 'multi-line'], 'dot-notation': 'error', 'eol-last': 'error', 'eqeqeq': ['error', 'smart'], 'guard-for-in': 'error', 'indent': ['error', 2, { SwitchCase: 1, VariableDeclarator: { var: 2, let: 2, const: 3 } }], 'key-spacing': ['error', { beforeColon: false, afterColon: true }], 'keyword-spacing': 'error', // 'max-len': ['warn', 120], 'no-alert': 'error', 'no-caller': 'error', 'no-catch-shadow': 'error', 'no-console': 'warn', 'no-else-return': 'error', 'no-empty': ['error', { allowEmptyCatch: true }], 'no-eval': 'error', 'no-extend-native': 'error', 'no-extra-bind': 'error', 'no-extra-parens': 'warn', 'no-fallthrough': 'error', 'no-floating-decimal': 'error', 'no-implied-eval': 'error', 'no-inner-declarations': ['error', 'both'], 'no-lonely-if': 'error', 'no-loop-func': 'error', 'no-mixed-spaces-and-tabs': 'error', 'no-multi-spaces': 'error', 'no-multiple-empty-lines': ['error', { max: 2 }], 'no-negated-condition': 'error', 'no-param-reassign': 'warn', 'no-redeclare': 'error', 'no-return-assign': 'error', 'no-self-compare': 'error', 'no-sequences': 'error', 'no-shadow': ['error', { builtinGlobals: true }], 'no-shadow-restricted-names': 'error', 'no-spaced-func': 'error', 'no-trailing-spaces': 'error', 'no-undef': 'error', 'no-undefined': 'error', 'no-underscore-dangle': 'off', 'no-unused-vars': ['error', { vars: 'all', args: 'after-used' }], 'no-use-before-define': ['error', 'nofunc'], 'no-useless-call': 'error', 'no-useless-escape': 'error', 'no-var': 'error', 'no-warning-comments': 'off', 'no-with': 'error', 'object-curly-spacing': ['error', 'always'], 'object-shorthand': ['error', 'always'], 'prefer-arrow-callback': ['error'], 'quotes': ['error', 'single'], 'semi': ['error', 'always'], 'semi-spacing': ['error', { before: false, after: true }], 'space-before-blocks': 'error', 'space-before-function-paren': ['error', { anonymous: 'always', named: 'never' }], 'space-in-parens': 'error', 'space-infix-ops': 'error', 'space-unary-ops': 'error', 'spaced-comment': ['warn', 'always', { block: { markers: ['!'], exceptions: ['*'] } }], 'strict': 'off', 'valid-jsdoc': 'warn', 'wrap-iife': ['error', 'outside'], 'yoda': ['error', 'never'], }, }; ================================================ FILE: .github/workflows/check.yml ================================================ name: check on: push: branches: - main pull_request: jobs: pre: name: Prerequisites if: github.event_name == 'pull_request' runs-on: ubuntu-latest steps: - name: Checkout uses: actions/checkout@v2 with: fetch-depth: 0 - name: Enforce CLA signature env: COMMIT_RANGE: ${{ github.event.pull_request.base.sha }}...${{ github.event.pull_request.head.sha }} run: curl https://raw.githubusercontent.com/shapesecurity/CLA/HEAD/cla-check.sh | bash check: needs: pre if: | !cancelled() && !failure() runs-on: ubuntu-latest strategy: matrix: node: [18] name: Check - node ${{ matrix.node }} steps: - name: Checkout uses: actions/checkout@v2 - name: Setup node uses: actions/setup-node@v2 with: node-version: ${{ matrix.node }} - name: Install dependencies run: npm ci - name: Lint run: npm run lint -- --quiet - name: Test run: npm test ================================================ FILE: .gitignore ================================================ node_modules ================================================ FILE: LICENSE ================================================ Apache License Version 2.0, January 2004 http://www.apache.org/licenses/ TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 1. 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While redistributing the Work or Derivative Works thereof, You may choose to offer, and charge a fee for, acceptance of support, warranty, indemnity, or other liability obligations and/or rights consistent with this License. However, in accepting such obligations, You may act only on Your own behalf and on Your sole responsibility, not on behalf of any other Contributor, and only if You agree to indemnify, defend, and hold each Contributor harmless for any liability incurred by, or claims asserted against, such Contributor by reason of your accepting any such warranty or additional liability. END OF TERMS AND CONDITIONS APPENDIX: How to apply the Apache License to your work. To apply the Apache License to your work, attach the following boilerplate notice, with the fields enclosed by brackets "[]" replaced with your own identifying information. (Don't include the brackets!) The text should be enclosed in the appropriate comment syntax for the file format. We also recommend that a file or class name and description of purpose be included on the same "printed page" as the copyright notice for easier identification within third-party archives. Copyright [yyyy] [name of copyright owner] Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. ================================================ FILE: README.md ================================================ Unminify ======== A little project to undo several of the horrible things JavaScript build tools will do to JavaScript. In addition to undoing most minification, it reverses some of the stupider but surprisingly common "obfuscation" techniques used in the wild. It may amuse you to try it on, say, [this random bit of JavaScript I found](https://secure2.homedepot.com/_bm/async.js). ## Installation ``` npm install -g unminify ``` or use it without installing via `npx` (available since `npm` 5.2.0) ``` npx unminify [...args] ``` ## CLI Usage ``` unminify /path/to/file.js ``` * `--safety` may be given to enable/disable transformations based on the user's required safety guarantees. Refer to the [safety levels](#safety-levels) documentation for more details. The value of `--safety` may be one of * `useless` * `safe` (default) * `mostly-safe` * `unsafe` * `wildly-unsafe` * `--additional-transform` may be given zero or more times, each followed by a path to a module providing an AST transform; the function signals that the transformation was not applied by returning its input ## API Usage ```js let { unminifySource } = require('unminify'); let sourceText = '/* a minified/"obfuscated" JavaScript program */'; console.log(unminify(sourceText)); // or, with options console.log(unminifySource(sourceText, { safety: unminify.safetyLevels.UNSAFE, additionalTransforms: [function(ast) { /* ... */ }], })); ``` If you already have a Shift tree then you can use `unminifyTree` to avoid the codegen & reparse cost. ```js let { parseScript } = require('shift-parser'); let { unminifyTree } = require('unminify'); let sourceText = '/* a minified/"obfuscated" JavaScript program */'; let tree = parseScript(sourceText); let unminifiedTree = unminifyTree(tree); ``` ## Safety Levels * "safe to the point of uselessness": * safe for ALL programs ("programs" don't have early errors) * "safe": "safe to the point of uselessness" except * Function.prototype.toString * function name/arity * Annex B * direct eval * "mostly safe": "safe" except * side effecting getters/setters on the global object * sealed global object * non-writable/non-configurable properties on the global object * top-level var decls make global properties * "unsafe": "mostly safe" except * non-spec built-in global properties or native proto properties * "wildly unsafe": * no guarantees but it'll probably work most of the time ## License Copyright 2017 Shape Security, Inc. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. ================================================ FILE: bin/cli.js ================================================ #!/usr/bin/env node require('../src/cli'); ================================================ FILE: package.json ================================================ { "name": "unminify", "version": "2.0.0", "author": "Kevin Gibbons ", "description": "reverse many of the transformations applied by minifiers and naïve obfuscators", "license": "Apache-2.0", "repository": { "type": "git", "url": "https://github.com/shapesecurity/unminify" }, "main": "src/index.js", "files": [ "src", "bin" ], "bin": "bin/cli.js", "scripts": { "test": "ava --fail-fast --verbose", "update-snapshots": "ava --update-snapshots", "lint": "eslint src bin", "build": "exit 0" }, "ava": { "files": [ "test/**/*.js", "!test/snapshots-*/**/*.js" ], "snapshotDir": "test/snapshots-out", "failFast": true, "failWithoutAssertions": false }, "dependencies": { "command-line-args": "5.2.1", "esutils": "2.0.3", "prettier": "2.6.2", "shift-ast": "7.0.0", "shift-codegen": "8.0.0", "shift-parser": "8.0.0", "shift-reducer": "7.0.0", "shift-scope": "6.0.0", "shift-spec": "2019.0.0" }, "devDependencies": { "ava": "4.2.0", "eslint": "8.15.0" } } ================================================ FILE: src/cli.js ================================================ 'use strict'; /* eslint-disable no-console */ const fs = require('fs'); const args = require('command-line-args')([ { name: 'file', type: String, defaultOption: true }, { name: 'safety', type: String, defaultValue: 'safe' }, { name: 'additional-transform', type: String, multiple: true, defaultValue: [] }, ]); const prettier = require('prettier'); const deobfuscate = require('../'); const safetyLevels = require('./safety-levels'); const safetyLevelMap = { __proto__: null, useless: safetyLevels.USELESS, safe: safetyLevels.SAFE, 'mostly-safe': safetyLevels.MOSTLY_SAFE, unsafe: safetyLevels.UNSAFE, 'wildly-unsafe': safetyLevels.WILDLY_UNSAFE, }; function format(src) { return prettier.format(src, { parser: 'babel', singleQuote: true, trailingComma: 'es5' }); } if (!args.file) { throw new Error('Missing required input file parameter'); } if (!(args.safety in safetyLevelMap)) { throw new Error(`Safety level must be one of ${JSON.stringify(Object.keys(safetyLevelMap))}`); } const src = fs.readFileSync(args.file, 'utf-8'); const safety = safetyLevelMap[args.safety]; const additionalTransforms = args['additional-transform'].map(a => require(a)); console.log(format(deobfuscate(src, { additionalTransforms, safety })).trim()); ================================================ FILE: src/helpers/codegen.js ================================================ 'use strict'; const codegen = require('shift-codegen'); class FormattedCodeGenWithStrs extends codegen.FormattedCodeGen { reduceLiteralStringExpression(node) { const s = super.reduceLiteralStringExpression(node); let out = ''; for (let i = 0; i < s.token.length; ++i) { const code = s.token.codePointAt(i); if (code >= 0x20 && code <= 0x7E) { out += s.token.charAt(i); } else if (code > 0xFFFF) { ++i; out += '\\u{' + code.toString(16).toUpperCase() + '}'; } else if (code > 0xFF) { let hex = code.toString(16).toUpperCase(); out += '\\u' + '0000'.slice(hex.length) + hex; } else if (code === 0) { out += '\\0'; } else { let hex = code.toString(16).toUpperCase(); out += '\\x' + '00'.slice(hex.length) + hex; } } s.token = out; return s; } } module.exports = function (tree) { return codegen.default(tree, new FormattedCodeGenWithStrs); }; ================================================ FILE: src/helpers/fn-contains-weirdness.js ================================================ 'use strict'; // TODO short-curcuiting, memoization const reducer = require('shift-reducer'); class ContainsWeirdness extends reducer.MonoidalReducer { constructor() { super({ empty: () => false, concat(b) { return this || b; } }); } reduceThisExpression() { return true; } reduceFunctionExpression() { return false; } reduceFunctionDeclaration() { return false; } reduceIdentifierExpression(node) { return node.name === 'arguments'; } // TODO many other cases } ContainsWeirdness.INSTANCE = new ContainsWeirdness; module.exports.functionContainsWeirdness = function (fn) { return reducer.default(ContainsWeirdness.INSTANCE, fn.params) || reducer.default(ContainsWeirdness.INSTANCE, fn.body); }; module.exports.expressionContainsWeirdness = function (expr) { return reducer.default(ContainsWeirdness.INSTANCE, expr); }; ================================================ FILE: src/helpers/inlinable.js ================================================ module.exports = [ 'LiteralNumericExpression', 'LiteralStringExpression', 'LiteralNullExpression', 'LiteralBooleanExpression', ]; ================================================ FILE: src/helpers/parents.js ================================================ 'use strict'; // Give a map from a node to its parents. const reducer = require('shift-reducer'); const spec = require('shift-spec'); class ParentFinder { constructor() { this.parents = new WeakMap; } } // eslint-disable-next-line guard-for-in for (const typeName in spec) { const type = spec[typeName]; const fields = type.fields.filter(f => f.name !== 'type'); ParentFinder.prototype['reduce' + typeName] = function (node) { for (const field of fields) { if (node[field.name] === null || typeof node[field.name] !== 'object') continue; if (Array.isArray(node[field.name])) { node[field.name].filter(c => c !== null).forEach(c => { this.parents.set(c, node); }); } else { this.parents.set(node[field.name], node); } } }; } ParentFinder.prototype.originalReduceScript = ParentFinder.prototype.reduceScript; ParentFinder.prototype.originalReduceModule = ParentFinder.prototype.reduceModule; ParentFinder.prototype.reduceScript = function (node) { this.originalReduceScript(node); this.parents.set(node, null); return this.parents; }; ParentFinder.prototype.reduceModule = function (node) { this.originalReduceModule(node); this.parents.set(node, null); return this.parents; }; module.exports = ast => reducer.default(new ParentFinder, ast); ================================================ FILE: src/index.js ================================================ 'use strict'; const parser = require('shift-parser'); const codegen = require('./helpers/codegen'); const safetyLevels = require('./safety-levels'); const TRANSFORMATIONS = { [safetyLevels.USELESS]: [], [safetyLevels.SAFE]: [ require('./transforms/safe/cleanup'), require('./transforms/safe/cleanup-with-state'), ], [safetyLevels.MOSTLY_SAFE]: [], [safetyLevels.UNSAFE]: [ require('./transforms/unsafe/remove-unused'), ], [safetyLevels.WILDLY_UNSAFE]: [ require('./transforms/wildly-unsafe/inline'), require('./transforms/wildly-unsafe/partial-evaluate'), ], }; function unminifySource(src, options) { let tree = parser.parseScript(src); return codegen(unminifyTree(tree, options)); } function unminifyTree(tree, { safety = safetyLevels.SAFE, additionalTransforms = [] } = {}) { let transformations = []; for (let i = 0; i <= safety; ++i) { transformations.push(...TRANSFORMATIONS[i]); } transformations.push(...additionalTransforms); let lastTree = tree; // cap at 100 on general principles, but theoretically `while (true)` should be ok for (let i = 0; i < 100; ++i) { let newTree = lastTree; for (let transformation of transformations) { newTree = transformation(newTree); } if (newTree === lastTree) break; lastTree = newTree; } return lastTree; } module.exports = unminifySource; module.exports.unminifySource = unminifySource; module.exports.unminifyTree = unminifyTree; module.exports.safetyLevels = safetyLevels; ================================================ FILE: src/safety-levels.js ================================================ module.exports = { __proto__: null, USELESS: 0, SAFE: 1, MOSTLY_SAFE: 2, UNSAFE: 3, WILDLY_UNSAFE: 4, }; ================================================ FILE: src/transforms/safe/cleanup-with-state.js ================================================ 'use strict'; const reducer = require('shift-reducer'); const shiftScope = require('shift-scope'); const Shift = require('shift-ast/checked'); const getParents = require('../../helpers/parents'); const { functionContainsWeirdness, expressionContainsWeirdness } = require('../../helpers/fn-contains-weirdness'); // TODO rename this to something better expressing "transform for simpler static analysis" module.exports = function cleanupWithState(ast) { const parents = getParents(ast); const globalScope = shiftScope.default(ast); const lookup = new shiftScope.ScopeLookup(globalScope); function findScopeForNode(node, scope = globalScope) { // TODO this should live elsewhere if (scope.astNode === node) return scope; for (let child of scope.children) { const r = findScopeForNode(node, child); if (r !== null) return r; } return null; } function unhoistVarDeclarations(statements) { const out = []; const toRemove = new WeakSet; const toBecomeDecl = new WeakMap; // ExpressionStatement -> list of other expression statements to remove from this set let touched = false; for (let statement of statements) { if (statement.type === 'VariableDeclarationStatement' && statement.declaration.kind === 'var' && statement.declaration.declarators.length === 1 && statement.declaration.declarators[0].init === null) { const vs = lookup.lookup(statement.declaration.declarators[0].binding); if (vs != null && vs.length === 1) { const v = vs[0]; const simpleWrites = v.references .filter(r => r.accessibility.isWrite && !r.accessibility.isRead) .map(r => parents.get(r.node)) .filter(n => n.type === 'AssignmentExpression') .map(n => [n, parents.get(n)]) .filter(([n, p]) => p.type === 'ExpressionStatement' || p.type === 'ForStatement' && p.init === n) .map(([, p]) => p); const declParent = parents.get(statement); const isSameParent = n => { const parent = parents.get(n); if (parent === declParent) { return true; } const gp = parents.get(parent); if (gp != null && gp.type === 'ForStatement' && gp.init === parent) { return true; } return false; }; if (simpleWrites.length > 0 && simpleWrites.every(isSameParent)) { touched = true; toRemove.add(statement); simpleWrites.forEach(s => toBecomeDecl.set(s, simpleWrites)); } } } } if (!touched) { return statements; } for (let statement of statements) { if (toRemove.has(statement)) continue; if (toBecomeDecl.has(statement)) { if (statement.type === 'ExpressionStatement') { const declaration = new Shift.VariableDeclaration({ kind: 'var', declarators: [new Shift.VariableDeclarator({ binding: new Shift.BindingIdentifier({ name: statement.expression.binding.name }), init: statement.expression.expression, })] }); out.push(new Shift.VariableDeclarationStatement({ declaration })); } else if (statement.type === 'ForStatement') { const declaration = new Shift.VariableDeclaration({ kind: 'var', declarators: [new Shift.VariableDeclarator({ binding: new Shift.BindingIdentifier({ name: statement.init.binding.name }), init: statement.init.expression, })] }); out.push(new Shift.ForStatement({ init: declaration, test: statement.test, update: statement.update, body: statement.body })); } else { throw new Error('unreachable'); } toBecomeDecl.get(statement).forEach(s => toBecomeDecl.delete(s)); continue; } out.push(statement); } return out; } class CleanupWithState extends reducer.LazyCloneReducer { reduceFunctionBody(node, { directives, statements }) { // move declarations to first initialization, as long as all writes are in the same statement list as the declaration return super.reduceFunctionBody(node, { directives, statements: unhoistVarDeclarations(statements) }); } reduceCallExpression(node, { callee, arguments: _arguments }) { // Turn (function(a){ ... })(b) into (function(){ var a = b; ... })() // Note: not safe if the function contains a direct `eval` which references `arguments` or an argument contains a direct `eval` which references `arguments` or `this`. if (callee.type === 'FunctionExpression' && !callee.isGenerator && !functionContainsWeirdness(callee)) { if (_arguments.length > 0 && _arguments.every(a => a.type !== 'SpreadElement' && !expressionContainsWeirdness(a)) && callee.params.rest === null && callee.params.items.every(p => p.type === 'BindingIdentifier')) { const names = [].concat(...node.arguments.map(collectNames)); // TODO avoid const fnScope = findScopeForNode(node.callee); if (fnScope && !names.some(n => fnScope.variables.has(n))) { // the scope check is to avoid shadowing something in the arguments const newInit = []; let i = 0; for (; i < callee.params.items.length; ++i) { newInit.push(new Shift.VariableDeclarationStatement({ declaration: new Shift.VariableDeclaration({ kind: 'var', declarators: [ new Shift.VariableDeclarator({ binding: callee.params.items[i], init: _arguments[i] || null }), ], }) })); } for (; i < _arguments.length; ++i) { newInit.push(new Shift.ExpressionStatement({ expression: _arguments[i] })); } const fn = new Shift.FunctionExpression({ name: callee.name, isGenerator: false, isAsync: false, params: new Shift.FormalParameters({ items: [], rest: null }), body: new Shift.FunctionBody({ directives: [], statements: newInit.concat(callee.body.statements), }) }); return new Shift.CallExpression({ callee: fn, arguments: [] }); } } } return super.reduceCallExpression(node, { callee, arguments: _arguments }); } } class NameCollector extends reducer.MonoidalReducer { constructor() { super({ empty: () => [], concat: (a, b) => a.concat(b) }); } reduceIdentifierExpression(node) { return [node.name]; } reduceAssignmentTargetIdentifier(node) { return [node.name]; } reduceBindingIdentifier(node) { return [node.name]; } reduceFunctionExpression(node, state) { // TODO it would be nice for this to be thunked const scope = findScopeForNode(node); if (scope !== null) { return [...scope.through.keys()]; } return super.reduceFunctionExpression(node, state); // better than nothing } /* Maybe this is a thing which should be exposed by the scope analyzer? through references for individual nodes, not just scopes? */ } function collectNames(node) { return reducer.default(new NameCollector, node); } return reducer.default(new CleanupWithState, ast); }; ================================================ FILE: src/transforms/safe/cleanup.js ================================================ 'use strict'; /* eslint-disable no-param-reassign */ // Basically de-uglify-js const reducer = require('shift-reducer'); const Shift = require('shift-ast/checked'); const inlinable = require('../../helpers/inlinable'); const { functionContainsWeirdness } = require('../../helpers/fn-contains-weirdness'); const esutils = require('esutils'); // TODO convert switches to if/else function makeBlock(statement) { return new Shift.BlockStatement({ block: new Shift.Block({ statements: [statement] }) }); } function negate(expr, isBooleanContext, requireResult = true) { if (expr.type === 'LiteralBooleanExpression') { return new Shift.LiteralBooleanExpression({ value: !expr.value }); } else if (expr.type === 'LiteralNumericExpression') { return new Shift.LiteralBooleanExpression({ value: !expr.value }); } else if (expr.type === 'ArrayExpression' && expr.elements.length === 0) { return new Shift.LiteralBooleanExpression({ value: false }); } else if (expr.type === 'ObjectExpression' && expr.properties.length === 0) { return new Shift.LiteralBooleanExpression({ value: false }); } else if (expr.type === 'BinaryExpression') { if (expr.operator === '&&') { return new Shift.BinaryExpression({ left: negate(expr.left, isBooleanContext), operator: '||', right: negate(expr.right, isBooleanContext) }); } else if (expr.operator === '||') { return new Shift.BinaryExpression({ left: negate(expr.left, isBooleanContext), operator: '&&', right: negate(expr.right, isBooleanContext) }); } else if (expr.operator === '==') { return new Shift.BinaryExpression({ left: expr.left, operator: '!=', right: expr.right }); } else if (expr.operator === '===') { return new Shift.BinaryExpression({ left: expr.left, operator: '!==', right: expr.right }); } else if (expr.operator === '!=') { return new Shift.BinaryExpression({ left: expr.left, operator: '==', right: expr.right }); } else if (expr.operator === '!==') { return new Shift.BinaryExpression({ left: expr.left, operator: '===', right: expr.right }); } } else if (expr.type === 'UnaryExpression' && expr.operator === '!' && isBooleanContext) { return { ...expr.operand }; } if (!requireResult) { return null; } return new Shift.UnaryExpression({ operator: '!', operand: expr }); } function isConstant(node) { return inlinable.includes(node.type) || node.type === 'UnaryExpression' && inlinable.includes(node.operand.type); } function isSequence(expr) { return expr != null && expr.type === 'BinaryExpression' && expr.operator === ','; } // NB: only for use with associative operators function binExprToExprs(expr) { const operator = expr.operator; return [...binExprToExprsHelper(expr.left, operator), ...binExprToExprsHelper(expr.right, operator)]; } function binExprToExprsHelper(expr, operator) { if (expr.type === 'BinaryExpression' && expr.operator === operator) { return [...binExprToExprsHelper(expr.left, operator), ...binExprToExprsHelper(expr.right, operator)]; } return [expr]; } function declaratorsToDeclarationStatements(kind, declarators) { return declarators.map(d => new Shift.VariableDeclarationStatement({ declaration: new Shift.VariableDeclaration({ kind, declarators: [d] }) })); } class OnlyReturnUndefined extends reducer.LazyCloneReducer { // TODO this would be better thunked. reduceFunctionBody(node) { return node; } reduceReturnStatement(node, { expression }) { if (expression === null || expression.type === 'UnaryExpression' && expression.operator === 'void') { return node; } if (expression.type === 'UnaryExpression' && expression.operator === 'void') { return node; } const undef = new Shift.UnaryExpression({ operator: 'void', operand: expression }); return new Shift.ReturnStatement({ expression: undef }); } } const onlyReturnUndefined = new OnlyReturnUndefined; function makeReturnsUndefined(fnBody) { const fixed = fnBody.statements.map(s => reducer.default(onlyReturnUndefined, s)); if (arrayEquals(fixed, fnBody.statements)) { return fnBody; } return new Shift.FunctionBody({ directives: fnBody.directives, statements: fixed }); } let booleanBinOps = ['==', '!=', '===', '!==', '<', '<=', '>', '>=', 'in', 'instanceof']; function returnsBoolean(expr) { return expr.type === 'LiteralBooleanExpression' || expr.type === 'UnaryExpression' && expr.operator === '!' || expr.type === 'BinaryExpression' && booleanBinOps.includes(expr.operator) || expr.type === 'BinaryExpression' && (expr.operator === '&&' || expr.operator === '||') && returnsBoolean(expr.left) && returnsBoolean(expr.right) || expr.type === 'BinaryExpression' && expr.operator === ',' && returnsBoolean(expr.right) || expr.type === 'ConditionalExpression' && returnsBoolean(expr.consequent) && returnsBoolean(expr.alternate); } /* This function takes an expression like a && (b, c, d) && e and returns an object with three properties: - prefix, a conjunction of all the clauses before the sequence expression, or `null` if there are none - seqs, a list of all expressions in the sequence expression save the last - suffix, a conjuction of the last item in the sequence expression with all the clauses after the sequence expression If the expression is not a conjunction of clauses at least one of which is a sequence, returns `null`. If `isBooleanContext` is true, it will additionally require that each clause in the prefix returns a boolean. In this example, assuming `isBooleanContext` is false, it would return { prefix: a seqs: [b, c] suffix: d && e } */ function extractSequenceFromConjunction(expr, isBooleanContext) { if (expr.type !== 'BinaryExpression' || expr.operator !== '&&') { return null; } const clauses = binExprToExprs(expr); for (let i = 0; i < clauses.length; ++i) { if (isSequence(clauses[i])) { const seqs = binExprToExprs(clauses[i]); const last = seqs.pop(); return { prefix: i === 0 ? null : clauses.slice(0, i).reduce((acc, e) => new Shift.BinaryExpression({ left: acc, operator: '&&', right: e })), seqs, suffix: clauses.slice(i + 1).reduce((acc, e) => new Shift.BinaryExpression({ left: acc, operator: '&&', right: e }), last), }; } if (!isBooleanContext && !returnsBoolean(clauses[i])) { break; } } return null; } function fixStatementList(statements) { // strip empty statements // turn sequence expressions in statement position into multiple statements // turn variable declarations with multiple declarators into multiple statements // for (var a, b, c;;); -> var a; var b; for (var c;;); const o = []; for (const s of statements) { switch (s.type) { case 'EmptyStatement': break; case 'TryCatchStatement': if (s.body.statements.length === 0) { o.push(new Shift.IfStatement({ test: new Shift.LiteralBooleanExpression({ value: false }), consequent: new Shift.BlockStatement({ block: s.catchClause.body }), alternate: null })); } else { o.push(s); } break; case 'ExpressionStatement': if (isSequence(s.expression)) { o.push(...binExprToExprs(s.expression).map(e => new Shift.ExpressionStatement({ expression: e }))); } else if (inlinable.includes(s.expression.type) || s.expression.type === 'ThisExpression' || s.expression.type === 'FunctionExpression') { // TODO local IdentifierExpressions continue; } else if (s.expression.type === 'UnaryExpression' && s.expression.operator === 'void') { if (inlinable.includes(s.expression.operand.type)) { continue; } o.push(new Shift.ExpressionStatement({ expression: s.expression.operand })); } else { o.push(s); } break; case 'ThrowStatement': if (isSequence(s.expression)) { const exprs = binExprToExprs(s.expression); const last = exprs.pop(); o.push(...exprs.map(e => new Shift.ExpressionStatement({ expression: e }))); o.push(new Shift.ThrowStatement({ expression: last })); } else { o.push(s); } break; case 'ReturnStatement': if (s.expression === null) { o.push(s); } else if (isSequence(s.expression)) { const exprs = binExprToExprs(s.expression); const last = exprs.pop(); o.push(...exprs.map(e => new Shift.ExpressionStatement({ expression: e }))); o.push(new Shift.ReturnStatement({ expression: last })); } else if (s.expression.type === 'ConditionalExpression') { const consequent = new Shift.ReturnStatement({ expression: s.expression.consequent }); const alternate = new Shift.ReturnStatement({ expression: s.expression.alternate }); o.push(new Shift.IfStatement({ test: s.expression.test, consequent, alternate })); } else if (s.expression.type === 'BinaryExpression' && s.expression.operator === '&&') { const extracted = extractSequenceFromConjunction(s.expression, false); if (extracted === null) { o.push(s); } else { const { prefix, seqs, suffix } = extracted; if (prefix !== null) { o.push(new Shift.IfStatement({ test: negate(prefix, true), consequent: new Shift.BlockStatement({ block: new Shift.Block({ statements: [new Shift.ReturnStatement({ expression: new Shift.LiteralBooleanExpression({ value: false }) })] }) }), alternate: null, })); } o.push(...seqs.map(e => new Shift.ExpressionStatement({ expression: e }))); o.push(new Shift.ReturnStatement({ expression: suffix })); } } else if (s.expression.type === 'UnaryExpression' && s.expression.operator === 'void') { o.push(new Shift.ExpressionStatement({ expression: s.expression.operand })); o.push(new Shift.ReturnStatement({ expression: null })); } else { o.push(s); } // TODO: elsewhere, remove statements after returns (while preserving hoisted declarations) break; case 'BlockStatement': if (s.block.statements.every(x => x.type !== 'FunctionDeclaration' && (x.type !== 'VariableDeclarationStatement' || x.declaration.kind === 'var'))) { o.push(...s.block.statements); } else { o.push(s); } break; case 'IfStatement': if (isSequence(s.test)) { const exprs = binExprToExprs(s.test); const last = exprs.pop(); o.push(...exprs.map(e => new Shift.ExpressionStatement({ expression: e }))); o.push(new Shift.IfStatement({ test: last, consequent: s.consequent, alternate: s.alternate })); } else if (s.test.type === 'BinaryExpression' && s.test.operator === '&&' && s.alternate == null) { const extracted = extractSequenceFromConjunction(s.test, true); if (extracted === null) { o.push(s); } else { const { prefix, seqs, suffix } = extracted; let newStatements = seqs.map(e => new Shift.ExpressionStatement({ expression: e })); newStatements.push(new Shift.IfStatement({ test: suffix, consequent: s.consequent, alternate: null, })); if (prefix === null) { o.push(...newStatements); } else { o.push(new Shift.IfStatement({ test: prefix, consequent: new Shift.BlockStatement({ block: new Shift.Block({ statements: newStatements }) }), alternate: null, })); } } } else { o.push(s); } break; case 'VariableDeclarationStatement': if (s.declaration.declarators.length > 1) { o.push(...declaratorsToDeclarationStatements(s.declaration.kind, s.declaration.declarators)); } else if (isSequence(s.declaration.declarators[0].init)) { let originalDeclarator = s.declaration.declarators[0]; // Yes, these steps could be combined, but /shrug const exprs = binExprToExprs(originalDeclarator.init); const last = exprs.pop(); o.push(...exprs.map(e => new Shift.ExpressionStatement({ expression: e }))); const declarator = new Shift.VariableDeclarator({ binding: originalDeclarator.binding, init: last }); const declaration = new Shift.VariableDeclaration({ kind: s.declaration.kind, declarators: [declarator] }); o.push(new Shift.VariableDeclarationStatement({ declaration })); } else { o.push(s); } break; case 'ForStatement': if (s.init != null) { if (s.init.type === 'VariableDeclaration' && s.init.declarators.length > 1) { const declarators = [...s.init.declarators]; const finalDeclarator = declarators.pop(); const newDeclaration = new Shift.VariableDeclaration({ kind: s.init.kind, declarators: [finalDeclarator] }); o.push(...declaratorsToDeclarationStatements(s.init.kind, declarators)); o.push(new Shift.ForStatement({ init: newDeclaration, test: s.test, update: s.update, body: s.body })); } else if (isSequence(s.init)) { const exprs = binExprToExprs(s.init); const last = exprs.pop(); o.push(...exprs.map(e => new Shift.ExpressionStatement({ expression: e }))); o.push(new Shift.ForStatement({ init: last, test: s.test, update: s.update, body: s.body })); } else { o.push(s); } } break; default: o.push(s); } } if (arrayEquals(o, statements)) { return statements; } return o; } function arrayEquals(a, b) { return a.length === b.length && a.every((v, i) => v === b[i]); } function hoistFunctionDeclarations(statements) { const decls = []; const nonDecls = []; for (const statement of statements) { if (statement.type === 'FunctionDeclaration') { decls.push(statement); } else { nonDecls.push(statement); } } const o = decls.concat(nonDecls); if (arrayEquals(o, statements)) { return statements; } return o; } class Cleanup extends reducer.LazyCloneReducer { reduceBlock(node, { statements }) { return super.reduceBlock(node, { statements: fixStatementList(statements) }); } reduceSwitchCase(node, { test, consequent }) { return super.reduceSwitchCase(node, { test, consequent: fixStatementList(consequent) }); } reduceSwitchDefault(node, { consequent }) { return super.reduceSwitchDefault(node, { consequent: fixStatementList(consequent) }); } reduceFunctionBody(node, { directives, statements }) { statements = hoistFunctionDeclarations(fixStatementList(statements)); if (directives.length === 0 && statements.length === 1 && (statements[0].type === 'ExpressionStatement' || statements[0].type === 'ReturnStatement') && statements[0].expression != null && statements[0].expression.type === 'CallExpression' && statements[0].expression.arguments.length === 0) { const callee = statements[0].expression.callee; if (callee.type === 'FunctionExpression' && callee.name === null && callee.params.items.length === 0 && callee.params.rest === null && !functionContainsWeirdness(callee)) { return statements[0].type === 'ExpressionStatement' ? makeReturnsUndefined(callee.body) : callee.body; } } if (statements.length > 0 && statements[statements.length - 1].type === 'ReturnStatement' && statements[statements.length - 1].expression == null) { statements = statements.slice(0, -1); } return super.reduceFunctionBody(node, { directives, statements }); } reduceScript(node, { directives, statements }) { return super.reduceScript(node, { directives, statements: fixStatementList(statements) }); } reduceUnaryExpression(node, { operand }) { if (node.operator === '!') { const negated = negate(operand, false, false); if (negated) { return negated; } } return super.reduceUnaryExpression(node, { operand }); } reduceBinaryExpression(node, { left, right }) { // 1 == a -> a == 1 if (['==', '===', '!=', '!=='].includes(node.operator) && isConstant(left) && !isConstant(right)) { return new Shift.BinaryExpression({ left: right, operator: node.operator, right: left }); } if (node.operator === ',' && inlinable.includes(left.type)) { return right; } return super.reduceBinaryExpression(node, { left, right }); } reduceExpressionStatement(node, { expression }) { if (expression.type === 'ConditionalExpression') { return new Shift.IfStatement({ test: expression.test, consequent: new Shift.ExpressionStatement({ expression: expression.consequent }), alternate: new Shift.ExpressionStatement({ expression: expression.alternate }) }); } else if (expression.type === 'BinaryExpression' && expression.operator === '&&') { return new Shift.IfStatement({ test: expression.left, consequent: new Shift.ExpressionStatement({ expression: expression.right }), alternate: null }); } else if (expression.type === 'BinaryExpression' && expression.operator === '||') { return new Shift.IfStatement({ test: new Shift.UnaryExpression({ operator: '!', operand: expression.left }), consequent: new Shift.ExpressionStatement({ expression: expression.right }), alternate: null }); } else if (expression.type === 'UnaryExpression' && expression.operator === '!') { return new Shift.ExpressionStatement({ expression: expression.operand }); } return super.reduceExpressionStatement(node, { expression }); } reduceIfStatement(node, { test, consequent, alternate }) { if (test.type === 'UnaryExpression' && test.operator === '!') { test = negate(test.operand, true, false) || test; } if (test.type === 'BinaryExpression' && (test.operator === '!=' || test.operator === '!==') && alternate != null) { test = negate(test, true); [consequent, alternate] = [alternate, consequent]; } if (consequent.type !== 'BlockStatement') { consequent = makeBlock(consequent); } if (alternate != null) { if (alternate.type !== 'BlockStatement' && alternate.type !== 'IfStatement') { alternate = makeBlock(alternate); } else if (alternate.type === 'BlockStatement' && alternate.block.statements.length === 1 && alternate.block.statements[0].type === 'IfStatement') { alternate = alternate.block.statements[0]; } if (alternate.type === 'BlockStatement' && alternate.block.statements.length === 0) { alternate = null; } } return super.reduceIfStatement(node, { test, consequent, alternate }); } reduceConditionalExpression(node, { test, consequent, alternate }) { if (test.type === 'UnaryExpression' && test.operator === '!') { test = negate(test.operand, true, false) || test; } return super.reduceConditionalExpression(node, { test, consequent, alternate }); } reduceForStatement(node, { init, test, update, body }) { if (body.type !== 'BlockStatement') { body = makeBlock(body); } if (init == null && test != null && update == null) { return new Shift.WhileStatement({ test, body }); } return super.reduceForStatement(node, { init, test, update, body }); } reduceForInStatement(node, { left, right, body }) { if (body.type !== 'BlockStatement') { body = makeBlock(body); } return super.reduceForInStatement(node, { left, right, body }); } reduceForOfStatement(node, { left, right, body }) { if (body.type !== 'BlockStatement') { body = makeBlock(body); } return super.reduceForOfStatement(node, { left, right, body }); } reduceWhileStatement(node, { test, body }) { if (body.type !== 'BlockStatement') { body = makeBlock(body); } return super.reduceWhileStatement(node, { test, body }); } reduceDoWhileStatement(node, { body, test }) { if (body.type !== 'BlockStatement') { body = makeBlock(body); } return super.reduceDoWhileStatement(node, { body, test }); } reduceComputedMemberAssignmentTarget(node, { object, expression }) { if (expression.type === 'LiteralStringExpression' && esutils.keyword.isIdentifierNameES6(expression.value)) { return new Shift.StaticMemberAssignmentTarget({ object, property: expression.value }); } return super.reduceComputedMemberAssignmentTarget(node, { object, expression }); } reduceComputedMemberExpression(node, { object, expression }) { if (expression.type === 'LiteralStringExpression' && esutils.keyword.isIdentifierNameES6(expression.value)) { return new Shift.StaticMemberExpression({ object, property: expression.value }); } return super.reduceComputedMemberExpression(node, { object, expression }); } reduceCallExpression(node, { callee, arguments: _arguments }) { if (callee.type === 'FunctionExpression' && !callee.isGenerator && !functionContainsWeirdness(callee)) { if (_arguments.length === 0 && callee.params.rest === null && callee.params.items.length === 0 && callee.body.directives.length === 0 && callee.body.statements.length <= 1) { // turn iifes with very simple bodies into expressions with no calls if (callee.body.statements.length === 0) { return new Shift.UnaryExpression({ operator: 'void', operand: new Shift.LiteralNullExpression }); } const statement = callee.body.statements[0]; if (statement.type === 'ReturnStatement') { return statement.expression; } if (statement.type === 'ExpressionStatement') { return new Shift.BinaryExpression({ left: statement.expression, operator: ',', right: new Shift.UnaryExpression({ operator: 'void', operand: new Shift.LiteralNullExpression }) }); // `(expr, void 0)` } } } return super.reduceCallExpression(node, { callee, arguments: _arguments }); } } const cleaner = new Cleanup; module.exports = function cleanup(ast) { return reducer.default(cleaner, ast); }; ================================================ FILE: src/transforms/unsafe/remove-unused.js ================================================ 'use strict'; // Remove unused variables and object properties which are initialized to constants. const scope = require('shift-scope'); const reducer = require('shift-reducer'); const Shift = require('shift-ast/checked'); const getParents = require('../../helpers/parents'); const inlinable = require('../../helpers/inlinable'); function isOnlyWritten(node, parents, lookup) { if (node.type !== 'AssignmentTargetIdentifier') { return false; } const vs = lookup.lookup(node); if (vs.length === 1 && lookup.scope.variableList.indexOf(vs[0]) === -1) { const reads = vs[0].references.filter(r => r.accessibility.isRead); return reads.length === 0 || reads.every(r => { if (!r.accessibility.isWrite) { return false; } const parent = parents.get(r.node); if (parent == null || !(parent.type === 'CompoundAssignmentExpression' || parent.type === 'UpdateExpression')) { return false; } const gp = parents.get(parent); return gp.type === 'ExpressionStatement'; }); } return false; } module.exports = function removeUnused(ast) { const globalScope = scope.default(ast); const lookup = new scope.ScopeLookup(globalScope); const parents = getParents(ast); class RemoveUnused extends reducer.LazyCloneReducer { reduceVariableDeclarationStatement(node, { declaration }) { // This strips declarations of variables initialized to constants if those variables are never referred to. const declarators = declaration.declarators.filter((d, i) => { const oldD = node.declaration.declarators[i]; if (d.binding.type !== 'BindingIdentifier' || d.init == null || !( inlinable.includes(d.init.type) || d.init.type === 'FunctionExpression' || d.init.type === 'ObjectExpression' && d.init.properties.length === 0 || d.init.type === 'ArrayExpression' && d.init.elements.every(e => inlinable.includes(e.type)) )) return true; const v = lookup.lookup(oldD.binding)[0]; if (v.declarations.length !== 1 || lookup.scope.variableList.includes(v)) return true; return v.references.length !== 1; }); if (declarators.length === 0) { return new Shift.EmptyStatement; } else if (declarators.length === 1) { const binding = declarators[0].binding; if (binding.type === 'BindingIdentifier') { const v = lookup.lookup(binding)[0]; if (v.references.every(ref => ref.node === binding) && !lookup.scope.variableList.includes(v)) { if (declarators[0].init === null) { return new Shift.EmptyStatement; } return new Shift.ExpressionStatement({ expression: declarators[0].init }); } } } if (declarators.length === declaration.declarators.length) { return super.reduceVariableDeclarationStatement(node, { declaration }); } return new Shift.VariableDeclarationStatement({ declaration: new Shift.VariableDeclaration({ kind: declaration.kind, declarators }) }); } reduceVariableDeclarator(node, { binding, init }) { // This strips properties from object literals used to initialize variables provided that // a.) no one ever refers to that variable except to read a static property of it, // b.) no one ever tries to read that property, and // c.) the object contains only data properties. // TODO make this safe by asserting that all properties ever referred to are present on the object (so they never go up to Object.prototype) if (init !== null && init.type === 'ObjectExpression' && init.properties.every(p => p.type === 'DataProperty')) { const v = lookup.lookup(node.binding)[0]; const referencedNames = new Set; if (v.references.every(r => { if (r.node === node.binding) return true; // We don't care about the declaration itself. const parent = parents.get(r.node); if (parent.type !== 'StaticMemberExpression') return false; referencedNames.add(parent.property); return true; })) { const properties = init.properties.filter(p => { return !(inlinable.includes(p.expression.type) || p.expression.type === 'FunctionExpression') || p.name.type !== 'StaticPropertyName' || referencedNames.has(p.name.value); }); if (properties.length === init.properties.length) { return super.reduceVariableDeclarator(node, { binding, init }); } const obj = new Shift.ObjectExpression({ properties }); return new Shift.VariableDeclarator({ binding, init: obj }); } } return super.reduceVariableDeclarator(node, { binding, init }); } reduceAssignmentExpression(node, { binding, expression }) { if (isOnlyWritten(node.binding, parents, lookup)) { return expression; } return super.reduceAssignmentExpression(node, { binding, expression }); } reduceCompoundAssignmentExpression(node, { binding, expression }) { if (isOnlyWritten(node.binding, parents, lookup)) { return expression; } return super.reduceCompoundAssignmentExpression(node, { binding, expression }); } } return reducer.default(new RemoveUnused, ast); }; ================================================ FILE: src/transforms/wildly-unsafe/inline.js ================================================ 'use strict'; // Inline constant primitive variables, constant primitive object properties, and constant object properties which are particularly trivial functions. const shiftScope = require('shift-scope'); const reducer = require('shift-reducer'); const Shift = require('shift-ast/checked'); const getParents = require('../../helpers/parents'); const inlinable = require('../../helpers/inlinable'); module.exports = function inline(ast) { const globalScope = shiftScope.default(ast); const lookup = new shiftScope.ScopeLookup(globalScope); const parents = getParents(ast); function findScopeForNode(node, scope = globalScope) { // TODO this should live elsewhere if (scope.astNode === node) return scope; for (let child of scope.children) { const r = findScopeForNode(node, child); if (r !== null) return r; } return null; } function isConstantInitializedVariable(v) { if (!isConstantVariable(v)) { return false; } const parent = parents.get(v.declarations[0].node); if (parent.type !== 'VariableDeclarator') { return false; } return parent.init !== null; } function isConstantVariable(v) { // TODO this also needs to check that use-before-def is impossible if (v.declarations.length !== 1) return false; const binding = v.declarations[0].node; const parent = parents.get(binding); if (parent.type !== 'VariableDeclarator' && parent.type !== 'FormalParameters') return false; if (v.references.some(r => r.accessibility.isWrite && r.node !== binding)) return false; return true; } function getConstantObjectVariableObject(_var) { // TODO for this to be actually correct we'd also need to check that none of the properties of the object are functions binding 'this' if (!isConstantInitializedVariable(_var)) return null; const binding = _var.declarations[0].node; const parent = parents.get(binding); if (parent.init == null) return null; if (parent.init.type === 'ObjectExpression' || parent.init.type === 'ArrayExpression') { if (_var.references.some(r => { const rparent = parents.get(r.node); return rparent.type === 'StaticMemberAssignmentTarget' || rparent.type === 'ComputedMemberAssignmentTarget' && rparent.object === r.node; })) return null; const obj = parent.init; if (obj.type === 'ObjectExpression') { return new Map(obj.properties.filter(p => p.type === 'DataProperty' && p.name.type === 'StaticPropertyName').map(p => [p.name.value, p.expression])); // TODO could include methods, in principle } else if (obj.type === 'ArrayExpression') { return new Map(obj.elements.map((v, i) => [i, v])); } throw 'not reached;'; } else { return null; } } function findStatementParent(node) { while (!/Statement/.test(node.type) && node.type !== 'FunctionDeclaration') { // eslint-disable-next-line no-param-reassign node = parents.get(node); } return node; } function getInlining(node) { const vars = lookup.lookup(node); if (vars.length !== 1) return null; const v = vars[0]; if (!isConstantInitializedVariable(v)) return null; const init = parents.get(v.declarations[0].node).init; if (init.type === 'IdentifierExpression') { const indirectVars = lookup.lookup(init); if (indirectVars.length === 1 && isConstantVariable(indirectVars[0])) { return new Shift.IdentifierExpression(init); } } if (!inlinable.includes(init.type)) return null; return { ...init }; } function getTriviallyInlineableFunction(f, arglen) { if (f.type !== 'FunctionExpression') return null; if (f.params.items.length !== arglen) return null; if (f.body.directives.length > 0) return null; if (f.body.statements.length !== 1) return null; if (f.body.statements[0].type !== 'ReturnStatement') return null; if (f.body.statements[0].expression.type !== 'BinaryExpression') return null; const expr = f.body.statements[0].expression; if (arglen === 2) { if (expr.left.type !== 'IdentifierExpression' || lookup.lookup(expr.left)[0] !== lookup.lookup(f.params.items[0])[0]) return null; if (expr.right.type !== 'IdentifierExpression' || lookup.lookup(expr.right)[0] !== lookup.lookup(f.params.items[1])[0]) return null; return (left, right) => new Shift.BinaryExpression({ left, operator: expr.operator, right }); } else if (arglen === 3) { if (expr.left.type !== 'BinaryExpression') return null; const expr2 = expr.left; if (expr2.left.type !== 'IdentifierExpression' || lookup.lookup(expr2.left)[0] !== lookup.lookup(f.params.items[0])[0]) return null; if (expr2.right.type !== 'IdentifierExpression' || lookup.lookup(expr2.right)[0] !== lookup.lookup(f.params.items[1])[0]) return null; if (expr.right.type !== 'IdentifierExpression' || lookup.lookup(expr.right)[0] !== lookup.lookup(f.params.items[2])[0]) return null; return (a, b, right) => new Shift.BinaryExpression({ left: new Shift.BinaryExpression({ left: a, operator: expr2.operator, right: b }), operator: expr.operator, right }); } return null; } class InliningReducer extends reducer.LazyCloneReducer { reduceExpressionStatement(node, { expression }) { if (expression.type === 'IdentifierExpression') { return new Shift.EmptyStatement; } return super.reduceExpressionStatement(node, { expression }); } reduceCallExpression(node, { callee, arguments: _arguments }) { if (callee.type === 'StaticMemberExpression' && callee.object.type === 'IdentifierExpression' && (_arguments.length === 2 || _arguments.length === 3)) { const vs = lookup.lookup(node.callee.object); if (vs.length === 1) { const obj = getConstantObjectVariableObject(vs[0]); if (obj !== null && obj.has(callee.property)) { const val = obj.get(callee.property); const replacer = getTriviallyInlineableFunction(val, _arguments.length); if (replacer !== null) { return replacer(..._arguments); } } } } else if (callee.type === 'IdentifierExpression') { const vs = lookup.lookup(node.callee); if (vs.length === 1 && isConstantInitializedVariable(vs[0]) && lookup.scope.variableList.indexOf(vs[0]) === -1) { const v = vs[0]; const decl = parents.get(v.declarations[0].node); if (decl.init.type === 'FunctionExpression') { const f = decl.init; let scope = findScopeForNode(f); if (scope !== null && scope.through.size === 0) { // This is to handle specifically `var x = function (foo) { if (foo == 'bar') { return a; } else { return b; } }; y = x('bar'); z = x('baz'); w = x();` if (f.params.items.length === 1 && _arguments.length <= 1) { const pv = lookup.lookup(f.params.items[0])[0]; if (pv.references.length === 1 && f.body.statements.length === 1 && f.body.statements[0].type === 'IfStatement') { const consequent = f.body.statements[0].consequent; const alternate = f.body.statements[0].alternate; if (consequent.type === 'BlockStatement' && consequent.block.statements.length === 1 && consequent.block.statements[0].type === 'ReturnStatement' && alternate.type === 'BlockStatement' && alternate.block.statements.length === 1 && alternate.block.statements[0].type === 'ReturnStatement') { const test = f.body.statements[0].test; if (test.type === 'BinaryExpression' && test.operator.slice(0, 2) === '==' && test.left.type === 'IdentifierExpression' && lookup.lookup(test.left)[0] === pv && inlinable.includes(test.right.type)) { const conditional = new Shift.ConditionalExpression({ test: { ...test }, consequent: consequent.block.statements[0].expression, alternate: alternate.block.statements[0].expression }); if (_arguments.length === 1) { conditional.test.left = _arguments[0]; } else { conditional.test.left = new Shift.UnaryExpression({ operator: 'void', operand: new Shift.LiteralNumericExpression({ value: 0 }) }); } return conditional; } } } } } if (v.references.length === 2) { // inline functions which are only called once const p1 = findStatementParent(v.references[0].node); const p2 = findStatementParent(v.references[0].node); if (scope.through.size === 0 || parents.get(p1) === parents.get(p2)) { // This ensures any through references get resolved the same after inlining return new Shift.CallExpression({ callee: reducer.default(new reducer.CloneReducer, f), arguments: _arguments }); } } } } } return super.reduceCallExpression(node, { callee, arguments: _arguments }); } reduceIdentifierExpression(node) { const inlining = getInlining(node); if (inlining !== null) return inlining; return super.reduceIdentifierExpression(node); } reduceComputedMemberExpression(node, { object, expression }) { if (node.object.type === 'IdentifierExpression' && expression.type === 'LiteralNumericExpression') { const vs = lookup.lookup(node.object); if (vs.length === 1) { const obj = getConstantObjectVariableObject(vs[0]); if (obj !== null && obj.has(expression.value)) { const val = obj.get(expression.value); if (inlinable.includes(val.type)) { return new Shift[val.type](val); } } } } return super.reduceComputedMemberExpression(node, { object, expression });// new Shift.ComputedMemberExpression({object, expression}); } reduceStaticMemberExpression(node, { object }) { if (node.object.type === 'IdentifierExpression') { const vs = lookup.lookup(node.object); if (vs.length === 1) { const obj = getConstantObjectVariableObject(vs[0]); if (obj !== null && obj.has(node.property)) { const val = obj.get(node.property); if (inlinable.includes(val.type)) { return { ...val }; } } } } return super.reduceStaticMemberExpression(node, { object }); } } return reducer.default(new InliningReducer, ast); }; ================================================ FILE: src/transforms/wildly-unsafe/partial-evaluate.js ================================================ 'use strict'; const reducer = require('shift-reducer'); const Shift = require('shift-ast/checked'); const shiftScope = require('shift-scope'); const getParents = require('../../helpers/parents'); const none = {}; function constantToNode(c) { switch (typeof c) { case 'undefined': return new Shift.UnaryExpression({ operator: 'void', operand: new Shift.LiteralNumericExpression({ value: 0 }) }); case 'number': return new Shift.LiteralNumericExpression({ value: c }); case 'string': return new Shift.LiteralStringExpression({ value: c }); case 'boolean': return new Shift.LiteralBooleanExpression({ value: c }); case 'object': if (Array.isArray(c)) { const elements = c.map(constantToNode); return new Shift.ArrayExpression({ elements }); } // falls through default: throw new Error('cannot handle ' + typeof c); } } const globalFunctions = { decodeURI, decodeURIComponent, unescape, parseInt, parseFloat, }; const isNonMutatingArrayMethod = p => ['slice', 'forEach', 'map', 'filter', 'reduce', 'indexOf'].includes(p); module.exports = function partialEvaluate(ast) { const parents = getParents(ast); const globalScope = shiftScope.default(ast); const lookup = new shiftScope.ScopeLookup(globalScope); function getStaticInit(node) { // This is unsafe in that it assumes no use-before-def const vs = lookup.lookup(node); if (vs && vs.length === 1) { const v = vs[0]; if (v.declarations.length === 1) { const binding = v.declarations[0].node; const parent = parents.get(binding); if (parent.type === 'VariableDeclarator' && parent.init !== null && v.references.every(r => !(r.accessibility.isWrite && r.node !== binding))) { return { initNode: parent.init, variable: v }; } } } return { initNode: null }; } function evaluateToNode(node) { const value = evaluate(node); if (value !== none && (typeof value !== 'object' || value === null) && typeof value !== 'function') { const rv = constantToNode(value); if (rv.type === 'UnaryExpression' && rv.type === node.type && rv.operator === 'void' && rv.operator === node.operator && rv.operand.type === 'LiteralNumericExpression' && rv.operand.type === node.operand.type && rv.operand.value === node.operand.value) { return node; } return rv; } return node; } const seen = new WeakMap; function evaluate(node) { if (seen.has(node)) { return seen.get(node); } seen.set(node, none); const out = evaluateCore(node); if (out !== none) { seen.set(node, out); } return out; } function evaluateCore(node) { switch (node.type) { case 'ArrayExpression': { const evaluated = node.elements.map(e => e === null ? void 0 : evaluate(e)); if (evaluated.every(v => v !== none)) { return evaluated; } break; } case 'LiteralNumericExpression': case 'LiteralStringExpression': case 'LiteralBooleanExpression': return node.value; case 'LiteralRegExpExpression': // Not actually safe, since regexps have identity if (!node.global && !node.ignoreCase && !node.multiLine && !node.sticky && !node.unicode) { return new RegExp(node.pattern); } break; case 'UnaryExpression': { const operand = evaluate(node.operand); if (operand !== none) { switch (node.operator) { case '+': return +operand; case 'void': return void 0; case '-': return -operand; case '!': return !operand; case '~': return ~operand; case 'typeof': return typeof operand; default: throw new Error('useful unary operator: ' + node.operator + ' ' + operand); } } break; } case 'BinaryExpression': { const left = evaluate(node.left); const right = evaluate(node.right); if (left !== none && right !== none) { switch (node.operator) { case '===': return left === right; case '!==': return left !== right; case '==': // eslint-disable-next-line eqeqeq return left == right; case '!=': // eslint-disable-next-line eqeqeq return left != right; case '>': return left > right; case '<': return left < right; case '>=': return left >= right; case '<=': return left <= right; case '+': return left + right; case '-': return left - right; case '*': return left * right; case '/': return left / right; case '%': return left % right; case '||': return left || right; case '&&': return left && right; case '<<': return left << right; case '>>': return left >> right; case '>>>': return left >>> right; case '|': return left | right; case '&': return left & right; case '^': return left ^ right; case 'in': // If this happens, something may have gone wrong. break; default: throw new Error('useful binary operator: ' + node.operator + ' ' + left + ' ' + right); } } break; } case 'IdentifierExpression': { if (node.name in globalFunctions) { const vs = lookup.lookup(node); if (vs.length === 1) { const refs = vs[0].references; if (vs[0].declarations.length === 0 && !refs.some(r => r.accessibility.isWrite)) { return globalFunctions[node.name]; } } } // TODO this isn't actually safe, for several reasons const { initNode, variable } = getStaticInit(node); if (initNode !== null) { const val = evaluate(initNode); if (val !== none) { if (Array.isArray(val)) { for (let r of variable.references) { let p = parents.get(r.node); if (p.type === 'StaticMemberExpression') { if (!(isNonMutatingArrayMethod(p.property) || p.property === 'length')) { return none; } } else if (p.type === 'StaticMemberAssignmentTarget' || p.type === 'ComputedMemberAssignmentTarget') { return none; } else if (p.type === 'ComputedMemberExpression') { const gp = parents.get(p); if (gp.type === 'CallExpression' && gp.callee === p) { return none; } } } } return val; } } break; } case 'CallExpression': { // TODO factor these cases better const argVals = node.arguments.map(evaluate); if (argVals.every(v => v !== none)) { if (node.callee.type === 'StaticMemberExpression') { // TODO factor this and similar cases out to something else if (node.callee.object.type === 'IdentifierExpression' && node.callee.object.name === 'String' && node.callee.property === 'fromCharCode' && node.arguments.length === 1 && node.arguments[0].type === 'LiteralNumericExpression') { return String.fromCharCode(node.arguments[0].value); } const objVal = evaluate(node.callee.object); if (objVal !== none) { if (typeof objVal !== 'object') { if (typeof objVal !== 'function') { return objVal[node.callee.property](...argVals); } } else if (Array.isArray(objVal) && isNonMutatingArrayMethod(node.callee.property)) { return objVal[node.callee.property](...argVals); } } } const calleeVal = evaluate(node.callee); if (typeof calleeVal === 'function') { let c = calleeVal(...argVals); return c; } } break; } case 'StaticMemberExpression': { if (node.property === 'length' && node.object.type === 'ArrayExpression') { return node.object.elements.length; } return evaluateStaticProperty(node.object, node.property); } } return none; } function evaluateStaticProperty(object, property) { // TODO this has a lot of overlap with inline.js // this interacts poorly with getters const objVal = evaluate(object); if (objVal !== none && typeof objVal !== 'object' && typeof objVal !== 'function') { if (property in Object(objVal)) { return objVal[property]; } return none; } if (object.type === 'IdentifierExpression') { const { initNode, variable } = getStaticInit(object); // TODO this is not sufficient; we also need to check it doesn't leak if (initNode !== null) { const leaks = variable.references.some(r => { if (r.accessibility.isRead) { const parent = parents.get(r.node); return parent.type !== 'StaticMemberExpression' && parent.type !== 'ComputedMemberAssignmentTarget' && parent.type !== 'StaticMemberAssignmentTarget' && parent.type !== 'ComputedMemberAssignmentTarget'; } return false; }); if (!leaks && (initNode.type === 'FunctionExpression' || initNode.type === 'ObjectExpression' && initNode.properties.every(p => p.type === 'DataProperty' && p.name.type === 'StaticPropertyName'))) { const hasComputedWrite = variable.references.some(r => { const parent = parents.get(r.node); return parent.type === 'ComputedMemberAssignmentTarget' && parent.object === r.node; }); if (!hasComputedWrite) { const hasProperty = initNode.type === 'ObjectExpression' && initNode.properties.filter(p => p.name.value === property).length === 1; const propertyWrites = variable.references.filter(r => { const parent = parents.get(r.node); return parent.type === 'StaticMemberAssignmentTarget' && parent.property === property; }); if (!hasProperty && propertyWrites.length === 1) { const gp = parents.get(parents.get(propertyWrites[0].node)); if (gp.type === 'AssignmentExpression') { return evaluate(gp.expression); } } else if (hasProperty && propertyWrites.length === 0) { for (let p of initNode.properties) { if (p.name.value === property) { return evaluate(p.expression); } } } } } } } return none; } class Evaluate extends reducer.LazyCloneReducer { reduceUnaryExpression(node, { operand }) { return evaluateToNode(super.reduceUnaryExpression(node, { operand })); } reduceBinaryExpression(node, { left, right }) { return evaluateToNode(super.reduceBinaryExpression(node, { left, right })); } reduceCallExpression(node, { callee, arguments: _arguments }) { return evaluateToNode(super.reduceCallExpression(node, { callee, arguments: _arguments })); } reduceStaticMemberExpression(node, { object }) { return evaluateToNode(super.reduceStaticMemberExpression(node, { object })); } reduceIdentifierExpression(node) { return evaluateToNode(node); } reduceComputedMemberExpression(node, { object, expression }) { const clone = super.reduceComputedMemberExpression(node, { object, expression }); const parent = parents.get(node); if (parent.type !== 'CallExpression' || parent.callee !== node) { if (object.type === 'ArrayExpression' || object.type === 'LiteralStringExpression') { const isArray = object.type === 'ArrayExpression'; const index = evaluate(expression); if (index !== none) { if (index === 'length') { return constantToNode((isArray ? object.elements : object.value).length); } const coerced = +('' + index); if (!Number.isNaN(coerced) && Math.floor(coerced) === coerced && coerced.toString() === '' + index) { if (coerced >= (isArray ? object.elements : object.value).length) { return constantToNode(void 0); } return isArray ? object.elements[index] : constantToNode(object.value[index]); } } } } return clone; } reduceConditionalExpression(node, { test, consequent, alternate }) { const clone = super.reduceConditionalExpression(node, { test, consequent, alternate }); const testValue = evaluate(clone.test); if (testValue !== none) { return testValue ? consequent : alternate; } return clone; } reduceIfStatement(node, { test, consequent, alternate }) { // Note: this needs to pull var declarations out of the untaken branch const clone = super.reduceIfStatement(node, { test, consequent, alternate }); const testValue = evaluate(clone.test); if (testValue !== none) { if (testValue) { return consequent; } if (alternate === null) { return new Shift.EmptyStatement; } return alternate; } return clone; } } return reducer.default(new Evaluate, ast); }; ================================================ FILE: test/snapshots-in/computed-member-to-static.js ================================================ a['b']; a['b'] = 0; a[0]; a['0']; ================================================ FILE: test/snapshots-in/expand-expression-statement.js ================================================ foo(), this, void bar(), void 0, new baz; ================================================ FILE: test/snapshots-in/expand-multiple-decl.js ================================================ function f(){ var a = foo(), b = bar(); for (var c = foo(), d = bar(); false;); return a + b + c + d; } ================================================ FILE: test/snapshots-in/expand-sequence.js ================================================ if(a(), b()) { c(); } function f(){ var a = (b(), c); return d(), a; } throw f(), g; for((a(), b()); false;); ================================================ FILE: test/snapshots-in/hoist-fns.js ================================================ function f(){ foo(); function bar(){} return bar; } ================================================ FILE: test/snapshots-in/if-and-seq.js ================================================ if (a && (b, c) && d) { foo(); } if ((b, c) && d) { foo(); } if (a && (b, c)) { foo(); } ================================================ FILE: test/snapshots-in/if-not.js ================================================ if (a !== b) { foo(); } else { bar(); } ================================================ FILE: test/snapshots-in/indexing.js ================================================ [0][0](); f([0, 1, 2][1]); f('abcd'[2]); f('' + [][0]); f('abcd'[5]); f([0, 1, 2].length); f('abcd'.length); f([].map); ================================================ FILE: test/snapshots-in/inline-arguments.js ================================================ (function(a, b){ return a + b; })(foo(), bar(), baz()); (function(a, b, c){ return a + b + c; })(foo(), bar()); ================================================ FILE: test/snapshots-in/inline-called-once.js ================================================ function f() { var x = function(a){ return a + foo(); } return x(a); } ================================================ FILE: test/snapshots-in/inline-constant-object-property.js ================================================ var x = { a: 0, }; y = x.a; ================================================ FILE: test/snapshots-in/inline-function-as-conditional.js ================================================ function f(){ var x = function (foo) { if (foo == 'bar') return 'a'; else return 'b'; }; var y = x(a); var z = x(b); var w = x(); return y + z + w; } ================================================ FILE: test/snapshots-in/inline-iife.js ================================================ function f () { (function() { foo(); })(); x = function(){ return 0; }(); x = function(){ foo(); }(); } ================================================ FILE: test/snapshots-in/inline-trivial-function.js ================================================ function f(){ var x = { p: function (a, b, c) { return a + b + c; }, }; console.log(x.p(foo(), bar(), baz())); } ================================================ FILE: test/snapshots-in/make-blocks.js ================================================ if (foo()) bar(); for(;;) bar(); while (0) bar(); for (a in b) bar(); do bar(); while (0); for (a of b) bar(); ================================================ FILE: test/snapshots-in/negate.js ================================================ f(!false); f(!0); f(![]); f(!(a && b)); f(!(a == b)); if (!!a) foo(); ================================================ FILE: test/snapshots-in/no-trailing-return-void.js ================================================ function f(){ foo(); return; } ================================================ FILE: test/snapshots-in/partial-evaluate.js ================================================ function f(){ var a = 1; return a + 2 + ['d', 'e']; } ================================================ FILE: test/snapshots-in/remove-empty-statements.js ================================================ ;; ================================================ FILE: test/snapshots-in/remove-empty-try.js ================================================ try{}catch(e){var x;} ================================================ FILE: test/snapshots-in/remove-unused-vars.js ================================================ var x = 0; function f(){ var x = foo(); } ================================================ FILE: test/snapshots-in/return-and.js ================================================ function f(){ return (a = 0, b, c) && d && e; } function g(){ return !a && b === 0 && (c = 0, d, e) && f && g; } function h(){ return !a && b === 0 && (c = 0, d, e); } function i(){ return a && (b, c); } ================================================ FILE: test/snapshots-in/return-conditional.js ================================================ function f(){ return foo() ? 0 : 1; } ================================================ FILE: test/snapshots-in/return-void.js ================================================ function f(){ if (foo()) { return void bar(); } } ================================================ FILE: test/snapshots-in/shorthand-if.js ================================================ a ? b() : c(); a && b(); a || c(); ================================================ FILE: test/snapshots-in/spread-block.js ================================================ { foo(); { bar(); baz(); } quux(); } ================================================ FILE: test/snapshots-in/statement-position-negation.js ================================================ !d(); ================================================ FILE: test/snapshots-in/un-yoda.js ================================================ 0 === b; ================================================ FILE: test/snapshots-in/unhoist-var-decls.js ================================================ function f(){ var a; b(); a = b(); return a; } ================================================ FILE: test/snapshots-out/test/snapshots.js.md ================================================ # Snapshot report for `test/snapshots.js` The actual snapshot is saved in `snapshots.js.snap`. Generated by [AVA](https://avajs.dev). ## USELESS snapshot: computed-member-to-static.js > Snapshot 1 `a['b'];␊ a['b'] = 0;␊ a[0];␊ a['0'];␊ ` ## SAFE snapshot: computed-member-to-static.js > Snapshot 1 `a.b;␊ a.b = 0;␊ a[0];␊ a['0'];␊ ` ## MOSTLY_SAFE snapshot: computed-member-to-static.js > Snapshot 1 `a.b;␊ a.b = 0;␊ a[0];␊ a['0'];␊ ` ## UNSAFE snapshot: computed-member-to-static.js > Snapshot 1 `a.b;␊ a.b = 0;␊ a[0];␊ a['0'];␊ ` ## WILDLY_UNSAFE snapshot: computed-member-to-static.js > Snapshot 1 `a.b;␊ a.b = 0;␊ a[0];␊ a['0'];␊ ` ## USELESS snapshot: expand-expression-statement.js > Snapshot 1 `foo(), this, void bar(), void 0, new baz();␊ ` ## SAFE snapshot: expand-expression-statement.js > Snapshot 1 `foo();␊ bar();␊ new baz();␊ ` ## MOSTLY_SAFE snapshot: expand-expression-statement.js > Snapshot 1 `foo();␊ bar();␊ new baz();␊ ` ## UNSAFE snapshot: expand-expression-statement.js > Snapshot 1 `foo();␊ bar();␊ new baz();␊ ` ## WILDLY_UNSAFE snapshot: expand-expression-statement.js > Snapshot 1 `foo();␊ bar();␊ new baz();␊ ` ## USELESS snapshot: expand-multiple-decl.js > Snapshot 1 `function f() {␊ var a = foo(),␊ b = bar();␊ for (var c = foo(), d = bar(); false; );␊ return a + b + c + d;␊ }␊ ` ## SAFE snapshot: expand-multiple-decl.js > Snapshot 1 `function f() {␊ var a = foo();␊ var b = bar();␊ var c = foo();␊ for (var d = bar(); false; ) {}␊ return a + b + c + d;␊ }␊ ` ## MOSTLY_SAFE snapshot: expand-multiple-decl.js > Snapshot 1 `function f() {␊ var a = foo();␊ var b = bar();␊ var c = foo();␊ for (var d = bar(); false; ) {}␊ return a + b + c + d;␊ }␊ ` ## UNSAFE snapshot: expand-multiple-decl.js > Snapshot 1 `function f() {␊ var a = foo();␊ var b = bar();␊ var c = foo();␊ for (var d = bar(); false; ) {}␊ return a + b + c + d;␊ }␊ ` ## WILDLY_UNSAFE snapshot: expand-multiple-decl.js > Snapshot 1 `function f() {␊ var a = foo();␊ var b = bar();␊ var c = foo();␊ for (var d = bar(); false; ) {}␊ return a + b + c + d;␊ }␊ ` ## USELESS snapshot: expand-sequence.js > Snapshot 1 `if ((a(), b())) {␊ c();␊ }␊ function f() {␊ var a = (b(), c);␊ return d(), a;␊ }␊ throw (f(), g);␊ for (a(), b(); false; );␊ ` ## SAFE snapshot: expand-sequence.js > Snapshot 1 `a();␊ if (b()) {␊ c();␊ }␊ function f() {␊ b();␊ var a = c;␊ d();␊ return a;␊ }␊ f();␊ throw g;␊ a();␊ for (b(); false; ) {}␊ ` ## MOSTLY_SAFE snapshot: expand-sequence.js > Snapshot 1 `a();␊ if (b()) {␊ c();␊ }␊ function f() {␊ b();␊ var a = c;␊ d();␊ return a;␊ }␊ f();␊ throw g;␊ a();␊ for (b(); false; ) {}␊ ` ## UNSAFE snapshot: expand-sequence.js > Snapshot 1 `a();␊ if (b()) {␊ c();␊ }␊ function f() {␊ b();␊ var a = c;␊ d();␊ return a;␊ }␊ f();␊ throw g;␊ a();␊ for (b(); false; ) {}␊ ` ## WILDLY_UNSAFE snapshot: expand-sequence.js > Snapshot 1 `a();␊ if (b()) {␊ c();␊ }␊ function f() {␊ b();␊ var a = c;␊ d();␊ return a;␊ }␊ f();␊ throw g;␊ a();␊ for (b(); false; ) {}␊ ` ## USELESS snapshot: hoist-fns.js > Snapshot 1 `function f() {␊ foo();␊ function bar() {}␊ return bar;␊ }␊ ` ## SAFE snapshot: hoist-fns.js > Snapshot 1 `function f() {␊ function bar() {}␊ foo();␊ return bar;␊ }␊ ` ## MOSTLY_SAFE snapshot: hoist-fns.js > Snapshot 1 `function f() {␊ function bar() {}␊ foo();␊ return bar;␊ }␊ ` ## UNSAFE snapshot: hoist-fns.js > Snapshot 1 `function f() {␊ function bar() {}␊ foo();␊ return bar;␊ }␊ ` ## WILDLY_UNSAFE snapshot: hoist-fns.js > Snapshot 1 `function f() {␊ function bar() {}␊ foo();␊ return bar;␊ }␊ ` ## USELESS snapshot: if-and-seq.js > Snapshot 1 `if (a && (b, c) && d) {␊ foo();␊ }␊ if ((b, c) && d) {␊ foo();␊ }␊ if (a && (b, c)) {␊ foo();␊ }␊ ` ## SAFE snapshot: if-and-seq.js > Snapshot 1 `if (a) {␊ b;␊ if (c && d) {␊ foo();␊ }␊ }␊ b;␊ if (c && d) {␊ foo();␊ }␊ if (a) {␊ b;␊ if (c) {␊ foo();␊ }␊ }␊ ` ## MOSTLY_SAFE snapshot: if-and-seq.js > Snapshot 1 `if (a) {␊ b;␊ if (c && d) {␊ foo();␊ }␊ }␊ b;␊ if (c && d) {␊ foo();␊ }␊ if (a) {␊ b;␊ if (c) {␊ foo();␊ }␊ }␊ ` ## UNSAFE snapshot: if-and-seq.js > Snapshot 1 `if (a) {␊ b;␊ if (c && d) {␊ foo();␊ }␊ }␊ b;␊ if (c && d) {␊ foo();␊ }␊ if (a) {␊ b;␊ if (c) {␊ foo();␊ }␊ }␊ ` ## WILDLY_UNSAFE snapshot: if-and-seq.js > Snapshot 1 `if (a) {␊ if (c && d) {␊ foo();␊ }␊ }␊ if (c && d) {␊ foo();␊ }␊ if (a) {␊ if (c) {␊ foo();␊ }␊ }␊ ` ## USELESS snapshot: if-not.js > Snapshot 1 `if (a !== b) {␊ foo();␊ } else {␊ bar();␊ }␊ ` ## SAFE snapshot: if-not.js > Snapshot 1 `if (a === b) {␊ bar();␊ } else {␊ foo();␊ }␊ ` ## MOSTLY_SAFE snapshot: if-not.js > Snapshot 1 `if (a === b) {␊ bar();␊ } else {␊ foo();␊ }␊ ` ## UNSAFE snapshot: if-not.js > Snapshot 1 `if (a === b) {␊ bar();␊ } else {␊ foo();␊ }␊ ` ## WILDLY_UNSAFE snapshot: if-not.js > Snapshot 1 `if (a === b) {␊ bar();␊ } else {␊ foo();␊ }␊ ` ## USELESS snapshot: indexing.js > Snapshot 1 `[0][0]();␊ f([0, 1, 2][1]);␊ f('abcd'[2]);␊ f('' + [][0]);␊ f('abcd'[5]);␊ f([0, 1, 2].length);␊ f('abcd'.length);␊ f([].map);␊ ` ## SAFE snapshot: indexing.js > Snapshot 1 `[0][0]();␊ f([0, 1, 2][1]);␊ f('abcd'[2]);␊ f('' + [][0]);␊ f('abcd'[5]);␊ f([0, 1, 2].length);␊ f('abcd'.length);␊ f([].map);␊ ` ## MOSTLY_SAFE snapshot: indexing.js > Snapshot 1 `[0][0]();␊ f([0, 1, 2][1]);␊ f('abcd'[2]);␊ f('' + [][0]);␊ f('abcd'[5]);␊ f([0, 1, 2].length);␊ f('abcd'.length);␊ f([].map);␊ ` ## UNSAFE snapshot: indexing.js > Snapshot 1 `[0][0]();␊ f([0, 1, 2][1]);␊ f('abcd'[2]);␊ f('' + [][0]);␊ f('abcd'[5]);␊ f([0, 1, 2].length);␊ f('abcd'.length);␊ f([].map);␊ ` ## WILDLY_UNSAFE snapshot: indexing.js > Snapshot 1 `[0][0]();␊ f(1);␊ f('c');␊ f('undefined');␊ f(void 0);␊ f(3);␊ f(4);␊ f([].map);␊ ` ## USELESS snapshot: inline-arguments.js > Snapshot 1 `(function (a, b) {␊ return a + b;␊ })(foo(), bar(), baz());␊ (function (a, b, c) {␊ return a + b + c;␊ })(foo(), bar());␊ ` ## SAFE snapshot: inline-arguments.js > Snapshot 1 `(function () {␊ var a = foo();␊ var b = bar();␊ baz();␊ return a + b;␊ })();␊ (function () {␊ var a = foo();␊ var b = bar();␊ var c;␊ return a + b + c;␊ })();␊ ` ## MOSTLY_SAFE snapshot: inline-arguments.js > Snapshot 1 `(function () {␊ var a = foo();␊ var b = bar();␊ baz();␊ return a + b;␊ })();␊ (function () {␊ var a = foo();␊ var b = bar();␊ var c;␊ return a + b + c;␊ })();␊ ` ## UNSAFE snapshot: inline-arguments.js > Snapshot 1 `(function () {␊ var a = foo();␊ var b = bar();␊ baz();␊ return a + b;␊ })();␊ (function () {␊ var a = foo();␊ var b = bar();␊ var c;␊ return a + b + c;␊ })();␊ ` ## WILDLY_UNSAFE snapshot: inline-arguments.js > Snapshot 1 `(function () {␊ var a = foo();␊ var b = bar();␊ baz();␊ return a + b;␊ })();␊ (function () {␊ var a = foo();␊ var b = bar();␊ var c;␊ return a + b + c;␊ })();␊ ` ## USELESS snapshot: inline-called-once.js > Snapshot 1 `function f() {␊ var x = function (a) {␊ return a + foo();␊ };␊ return x(a);␊ }␊ ` ## SAFE snapshot: inline-called-once.js > Snapshot 1 `function f() {␊ var x = function (a) {␊ return a + foo();␊ };␊ return x(a);␊ }␊ ` ## MOSTLY_SAFE snapshot: inline-called-once.js > Snapshot 1 `function f() {␊ var x = function (a) {␊ return a + foo();␊ };␊ return x(a);␊ }␊ ` ## UNSAFE snapshot: inline-called-once.js > Snapshot 1 `function f() {␊ var x = function (a) {␊ return a + foo();␊ };␊ return x(a);␊ }␊ ` ## WILDLY_UNSAFE snapshot: inline-called-once.js > Snapshot 1 `function f() {␊ return (function (a) {␊ return a + foo();␊ })(a);␊ }␊ ` ## USELESS snapshot: inline-constant-object-property.js > Snapshot 1 `var x = { a: 0 };␊ y = x.a;␊ ` ## SAFE snapshot: inline-constant-object-property.js > Snapshot 1 `var x = { a: 0 };␊ y = x.a;␊ ` ## MOSTLY_SAFE snapshot: inline-constant-object-property.js > Snapshot 1 `var x = { a: 0 };␊ y = x.a;␊ ` ## UNSAFE snapshot: inline-constant-object-property.js > Snapshot 1 `var x = { a: 0 };␊ y = x.a;␊ ` ## WILDLY_UNSAFE snapshot: inline-constant-object-property.js > Snapshot 1 `var x = {};␊ y = 0;␊ ` ## USELESS snapshot: inline-function-as-conditional.js > Snapshot 1 `function f() {␊ var x = function (foo) {␊ if (foo == 'bar') return 'a';␊ else return 'b';␊ };␊ var y = x(a);␊ var z = x(b);␊ var w = x();␊ return y + z + w;␊ }␊ ` ## SAFE snapshot: inline-function-as-conditional.js > Snapshot 1 `function f() {␊ var x = function (foo) {␊ if (foo == 'bar') {␊ return 'a';␊ } else {␊ return 'b';␊ }␊ };␊ var y = x(a);␊ var z = x(b);␊ var w = x();␊ return y + z + w;␊ }␊ ` ## MOSTLY_SAFE snapshot: inline-function-as-conditional.js > Snapshot 1 `function f() {␊ var x = function (foo) {␊ if (foo == 'bar') {␊ return 'a';␊ } else {␊ return 'b';␊ }␊ };␊ var y = x(a);␊ var z = x(b);␊ var w = x();␊ return y + z + w;␊ }␊ ` ## UNSAFE snapshot: inline-function-as-conditional.js > Snapshot 1 `function f() {␊ var x = function (foo) {␊ if (foo == 'bar') {␊ return 'a';␊ } else {␊ return 'b';␊ }␊ };␊ var y = x(a);␊ var z = x(b);␊ var w = x();␊ return y + z + w;␊ }␊ ` ## WILDLY_UNSAFE snapshot: inline-function-as-conditional.js > Snapshot 1 `function f() {␊ var y = a == 'bar' ? 'a' : 'b';␊ var z = b == 'bar' ? 'a' : 'b';␊ return y + z + 'b';␊ }␊ ` ## USELESS snapshot: inline-iife.js > Snapshot 1 `function f() {␊ (function () {␊ foo();␊ })();␊ x = (function () {␊ return 0;␊ })();␊ x = (function () {␊ foo();␊ })();␊ }␊ ` ## SAFE snapshot: inline-iife.js > Snapshot 1 `function f() {␊ foo();␊ x = 0;␊ x = (foo(), void null);␊ }␊ ` ## MOSTLY_SAFE snapshot: inline-iife.js > Snapshot 1 `function f() {␊ foo();␊ x = 0;␊ x = (foo(), void null);␊ }␊ ` ## UNSAFE snapshot: inline-iife.js > Snapshot 1 `function f() {␊ foo();␊ x = 0;␊ x = (foo(), void null);␊ }␊ ` ## WILDLY_UNSAFE snapshot: inline-iife.js > Snapshot 1 `function f() {␊ foo();␊ x = 0;␊ x = (foo(), void null);␊ }␊ ` ## USELESS snapshot: inline-trivial-function.js > Snapshot 1 `function f() {␊ var x = {␊ p: function (a, b, c) {␊ return a + b + c;␊ },␊ };␊ console.log(x.p(foo(), bar(), baz()));␊ }␊ ` ## SAFE snapshot: inline-trivial-function.js > Snapshot 1 `function f() {␊ var x = {␊ p: function (a, b, c) {␊ return a + b + c;␊ },␊ };␊ console.log(x.p(foo(), bar(), baz()));␊ }␊ ` ## MOSTLY_SAFE snapshot: inline-trivial-function.js > Snapshot 1 `function f() {␊ var x = {␊ p: function (a, b, c) {␊ return a + b + c;␊ },␊ };␊ console.log(x.p(foo(), bar(), baz()));␊ }␊ ` ## UNSAFE snapshot: inline-trivial-function.js > Snapshot 1 `function f() {␊ var x = {␊ p: function (a, b, c) {␊ return a + b + c;␊ },␊ };␊ console.log(x.p(foo(), bar(), baz()));␊ }␊ ` ## WILDLY_UNSAFE snapshot: inline-trivial-function.js > Snapshot 1 `function f() {␊ console.log(foo() + bar() + baz());␊ }␊ ` ## USELESS snapshot: make-blocks.js > Snapshot 1 `if (foo()) bar();␊ for (;;) bar();␊ while (0) bar();␊ for (a in b) bar();␊ do bar();␊ while (0);␊ for (a of b) bar();␊ ` ## SAFE snapshot: make-blocks.js > Snapshot 1 `if (foo()) {␊ bar();␊ }␊ while (0) {␊ bar();␊ }␊ for (a in b) {␊ bar();␊ }␊ do {␊ bar();␊ } while (0);␊ for (a of b) {␊ bar();␊ }␊ ` ## MOSTLY_SAFE snapshot: make-blocks.js > Snapshot 1 `if (foo()) {␊ bar();␊ }␊ while (0) {␊ bar();␊ }␊ for (a in b) {␊ bar();␊ }␊ do {␊ bar();␊ } while (0);␊ for (a of b) {␊ bar();␊ }␊ ` ## UNSAFE snapshot: make-blocks.js > Snapshot 1 `if (foo()) {␊ bar();␊ }␊ while (0) {␊ bar();␊ }␊ for (a in b) {␊ bar();␊ }␊ do {␊ bar();␊ } while (0);␊ for (a of b) {␊ bar();␊ }␊ ` ## WILDLY_UNSAFE snapshot: make-blocks.js > Snapshot 1 `if (foo()) {␊ bar();␊ }␊ while (0) {␊ bar();␊ }␊ for (a in b) {␊ bar();␊ }␊ do {␊ bar();␊ } while (0);␊ for (a of b) {␊ bar();␊ }␊ ` ## USELESS snapshot: negate.js > Snapshot 1 `f(!false);␊ f(!0);␊ f(![]);␊ f(!(a && b));␊ f(!(a == b));␊ if (!!a) foo();␊ ` ## SAFE snapshot: negate.js > Snapshot 1 `f(true);␊ f(true);␊ f(false);␊ f(!a || !b);␊ f(a != b);␊ if (a) {␊ foo();␊ }␊ ` ## MOSTLY_SAFE snapshot: negate.js > Snapshot 1 `f(true);␊ f(true);␊ f(false);␊ f(!a || !b);␊ f(a != b);␊ if (a) {␊ foo();␊ }␊ ` ## UNSAFE snapshot: negate.js > Snapshot 1 `f(true);␊ f(true);␊ f(false);␊ f(!a || !b);␊ f(a != b);␊ if (a) {␊ foo();␊ }␊ ` ## WILDLY_UNSAFE snapshot: negate.js > Snapshot 1 `f(true);␊ f(true);␊ f(false);␊ f(!a || !b);␊ f(a != b);␊ if (a) {␊ foo();␊ }␊ ` ## USELESS snapshot: no-trailing-return-void.js > Snapshot 1 `function f() {␊ foo();␊ return;␊ }␊ ` ## SAFE snapshot: no-trailing-return-void.js > Snapshot 1 `function f() {␊ foo();␊ }␊ ` ## MOSTLY_SAFE snapshot: no-trailing-return-void.js > Snapshot 1 `function f() {␊ foo();␊ }␊ ` ## UNSAFE snapshot: no-trailing-return-void.js > Snapshot 1 `function f() {␊ foo();␊ }␊ ` ## WILDLY_UNSAFE snapshot: no-trailing-return-void.js > Snapshot 1 `function f() {␊ foo();␊ }␊ ` ## USELESS snapshot: partial-evaluate.js > Snapshot 1 `function f() {␊ var a = 1;␊ return a + 2 + ['d', 'e'];␊ }␊ ` ## SAFE snapshot: partial-evaluate.js > Snapshot 1 `function f() {␊ var a = 1;␊ return a + 2 + ['d', 'e'];␊ }␊ ` ## MOSTLY_SAFE snapshot: partial-evaluate.js > Snapshot 1 `function f() {␊ var a = 1;␊ return a + 2 + ['d', 'e'];␊ }␊ ` ## UNSAFE snapshot: partial-evaluate.js > Snapshot 1 `function f() {␊ var a = 1;␊ return a + 2 + ['d', 'e'];␊ }␊ ` ## WILDLY_UNSAFE snapshot: partial-evaluate.js > Snapshot 1 `function f() {␊ return '3d,e';␊ }␊ ` ## USELESS snapshot: remove-empty-statements.js > Snapshot 1 '' ## SAFE snapshot: remove-empty-statements.js > Snapshot 1 '' ## MOSTLY_SAFE snapshot: remove-empty-statements.js > Snapshot 1 '' ## UNSAFE snapshot: remove-empty-statements.js > Snapshot 1 '' ## WILDLY_UNSAFE snapshot: remove-empty-statements.js > Snapshot 1 '' ## USELESS snapshot: remove-empty-try.js > Snapshot 1 `try {␊ } catch (e) {␊ var x;␊ }␊ ` ## SAFE snapshot: remove-empty-try.js > Snapshot 1 `if (false) {␊ var x;␊ }␊ ` ## MOSTLY_SAFE snapshot: remove-empty-try.js > Snapshot 1 `if (false) {␊ var x;␊ }␊ ` ## UNSAFE snapshot: remove-empty-try.js > Snapshot 1 `if (false) {␊ var x;␊ }␊ ` ## WILDLY_UNSAFE snapshot: remove-empty-try.js > Snapshot 1 '' ## USELESS snapshot: remove-unused-vars.js > Snapshot 1 `var x = 0;␊ function f() {␊ var x = foo();␊ }␊ ` ## SAFE snapshot: remove-unused-vars.js > Snapshot 1 `var x = 0;␊ function f() {␊ var x = foo();␊ }␊ ` ## MOSTLY_SAFE snapshot: remove-unused-vars.js > Snapshot 1 `var x = 0;␊ function f() {␊ var x = foo();␊ }␊ ` ## UNSAFE snapshot: remove-unused-vars.js > Snapshot 1 `var x = 0;␊ function f() {␊ foo();␊ }␊ ` ## WILDLY_UNSAFE snapshot: remove-unused-vars.js > Snapshot 1 `var x = 0;␊ function f() {␊ foo();␊ }␊ ` ## USELESS snapshot: return-and.js > Snapshot 1 `function f() {␊ return ((a = 0), b, c) && d && e;␊ }␊ function g() {␊ return !a && b === 0 && ((c = 0), d, e) && f && g;␊ }␊ function h() {␊ return !a && b === 0 && ((c = 0), d, e);␊ }␊ function i() {␊ return a && (b, c);␊ }␊ ` ## SAFE snapshot: return-and.js > Snapshot 1 `function f() {␊ a = 0;␊ b;␊ return c && d && e;␊ }␊ function g() {␊ if (a || b !== 0) {␊ return false;␊ }␊ c = 0;␊ d;␊ return e && f && g;␊ }␊ function h() {␊ if (a || b !== 0) {␊ return false;␊ }␊ c = 0;␊ d;␊ return e;␊ }␊ function i() {␊ return a && (b, c);␊ }␊ ` ## MOSTLY_SAFE snapshot: return-and.js > Snapshot 1 `function f() {␊ a = 0;␊ b;␊ return c && d && e;␊ }␊ function g() {␊ if (a || b !== 0) {␊ return false;␊ }␊ c = 0;␊ d;␊ return e && f && g;␊ }␊ function h() {␊ if (a || b !== 0) {␊ return false;␊ }␊ c = 0;␊ d;␊ return e;␊ }␊ function i() {␊ return a && (b, c);␊ }␊ ` ## UNSAFE snapshot: return-and.js > Snapshot 1 `function f() {␊ a = 0;␊ b;␊ return c && d && e;␊ }␊ function g() {␊ if (a || b !== 0) {␊ return false;␊ }␊ c = 0;␊ d;␊ return e && f && g;␊ }␊ function h() {␊ if (a || b !== 0) {␊ return false;␊ }␊ c = 0;␊ d;␊ return e;␊ }␊ function i() {␊ return a && (b, c);␊ }␊ ` ## WILDLY_UNSAFE snapshot: return-and.js > Snapshot 1 `function f() {␊ a = 0;␊ return c && d && e;␊ }␊ function g() {␊ if (a || b !== 0) {␊ return false;␊ }␊ c = 0;␊ return e && f && g;␊ }␊ function h() {␊ if (a || b !== 0) {␊ return false;␊ }␊ c = 0;␊ return e;␊ }␊ function i() {␊ return a && (b, c);␊ }␊ ` ## USELESS snapshot: return-conditional.js > Snapshot 1 `function f() {␊ return foo() ? 0 : 1;␊ }␊ ` ## SAFE snapshot: return-conditional.js > Snapshot 1 `function f() {␊ if (foo()) {␊ return 0;␊ } else {␊ return 1;␊ }␊ }␊ ` ## MOSTLY_SAFE snapshot: return-conditional.js > Snapshot 1 `function f() {␊ if (foo()) {␊ return 0;␊ } else {␊ return 1;␊ }␊ }␊ ` ## UNSAFE snapshot: return-conditional.js > Snapshot 1 `function f() {␊ if (foo()) {␊ return 0;␊ } else {␊ return 1;␊ }␊ }␊ ` ## WILDLY_UNSAFE snapshot: return-conditional.js > Snapshot 1 `function f() {␊ if (foo()) {␊ return 0;␊ } else {␊ return 1;␊ }␊ }␊ ` ## USELESS snapshot: return-void.js > Snapshot 1 `function f() {␊ if (foo()) {␊ return void bar();␊ }␊ }␊ ` ## SAFE snapshot: return-void.js > Snapshot 1 `function f() {␊ if (foo()) {␊ bar();␊ return;␊ }␊ }␊ ` ## MOSTLY_SAFE snapshot: return-void.js > Snapshot 1 `function f() {␊ if (foo()) {␊ bar();␊ return;␊ }␊ }␊ ` ## UNSAFE snapshot: return-void.js > Snapshot 1 `function f() {␊ if (foo()) {␊ bar();␊ return;␊ }␊ }␊ ` ## WILDLY_UNSAFE snapshot: return-void.js > Snapshot 1 `function f() {␊ if (foo()) {␊ bar();␊ return;␊ }␊ }␊ ` ## USELESS snapshot: shorthand-if.js > Snapshot 1 `a ? b() : c();␊ a && b();␊ a || c();␊ ` ## SAFE snapshot: shorthand-if.js > Snapshot 1 `if (a) {␊ b();␊ } else {␊ c();␊ }␊ if (a) {␊ b();␊ }␊ if (!a) {␊ c();␊ }␊ ` ## MOSTLY_SAFE snapshot: shorthand-if.js > Snapshot 1 `if (a) {␊ b();␊ } else {␊ c();␊ }␊ if (a) {␊ b();␊ }␊ if (!a) {␊ c();␊ }␊ ` ## UNSAFE snapshot: shorthand-if.js > Snapshot 1 `if (a) {␊ b();␊ } else {␊ c();␊ }␊ if (a) {␊ b();␊ }␊ if (!a) {␊ c();␊ }␊ ` ## WILDLY_UNSAFE snapshot: shorthand-if.js > Snapshot 1 `if (a) {␊ b();␊ } else {␊ c();␊ }␊ if (a) {␊ b();␊ }␊ if (!a) {␊ c();␊ }␊ ` ## USELESS snapshot: spread-block.js > Snapshot 1 `{␊ foo();␊ {␊ bar();␊ baz();␊ }␊ quux();␊ }␊ ` ## SAFE snapshot: spread-block.js > Snapshot 1 `foo();␊ bar();␊ baz();␊ quux();␊ ` ## MOSTLY_SAFE snapshot: spread-block.js > Snapshot 1 `foo();␊ bar();␊ baz();␊ quux();␊ ` ## UNSAFE snapshot: spread-block.js > Snapshot 1 `foo();␊ bar();␊ baz();␊ quux();␊ ` ## WILDLY_UNSAFE snapshot: spread-block.js > Snapshot 1 `foo();␊ bar();␊ baz();␊ quux();␊ ` ## USELESS snapshot: statement-position-negation.js > Snapshot 1 `!d();␊ ` ## SAFE snapshot: statement-position-negation.js > Snapshot 1 `d();␊ ` ## MOSTLY_SAFE snapshot: statement-position-negation.js > Snapshot 1 `d();␊ ` ## UNSAFE snapshot: statement-position-negation.js > Snapshot 1 `d();␊ ` ## WILDLY_UNSAFE snapshot: statement-position-negation.js > Snapshot 1 `d();␊ ` ## USELESS snapshot: un-yoda.js > Snapshot 1 `0 === b;␊ ` ## SAFE snapshot: un-yoda.js > Snapshot 1 `b === 0;␊ ` ## MOSTLY_SAFE snapshot: un-yoda.js > Snapshot 1 `b === 0;␊ ` ## UNSAFE snapshot: un-yoda.js > Snapshot 1 `b === 0;␊ ` ## WILDLY_UNSAFE snapshot: un-yoda.js > Snapshot 1 `b === 0;␊ ` ## USELESS snapshot: unhoist-var-decls.js > Snapshot 1 `function f() {␊ var a;␊ b();␊ a = b();␊ return a;␊ }␊ ` ## SAFE snapshot: unhoist-var-decls.js > Snapshot 1 `function f() {␊ b();␊ var a = b();␊ return a;␊ }␊ ` ## MOSTLY_SAFE snapshot: unhoist-var-decls.js > Snapshot 1 `function f() {␊ b();␊ var a = b();␊ return a;␊ }␊ ` ## UNSAFE snapshot: unhoist-var-decls.js > Snapshot 1 `function f() {␊ b();␊ var a = b();␊ return a;␊ }␊ ` ## WILDLY_UNSAFE snapshot: unhoist-var-decls.js > Snapshot 1 `function f() {␊ b();␊ var a = b();␊ return a;␊ }␊ ` ================================================ FILE: test/snapshots.js ================================================ const fs = require('fs'); const test = require('ava'); const prettier = require('prettier'); const unminify = require('../'); const SNAPSHOTS_DIR = `${__dirname}/snapshots-in`; const files = fs.readdirSync(SNAPSHOTS_DIR) function format(src) { return prettier.format(src, { parser: 'babel', singleQuote: true, trailingComma: 'all' }); } files.forEach(file => { let sourceText = fs.readFileSync(`${SNAPSHOTS_DIR}/${file}`, 'utf-8'); Object.keys(unminify.safetyLevels).forEach(safetyLevel => { test(`${safetyLevel} snapshot: ${file}`, async t => { t.snapshot(format(unminify(sourceText, { safety: unminify.safetyLevels[safetyLevel] }))); }); }); });