Repository: dappuniversity/ethers_examples
Branch: master
Commit: ba72b711ebdf
Files: 9
Total size: 7.6 KB

Directory structure:
gitextract_mhniizkg/

├── .gitignore
├── README.md
├── examples/
│   ├── 1_accounts.js
│   ├── 2_read_smart_contract.js
│   ├── 3_send_signed_transaction.js
│   ├── 4_write_contract.js
│   ├── 5_contract_event_stream.js
│   └── 6_inspecting_blocks.js
└── package.json

================================================
FILE CONTENTS
================================================

================================================
FILE: .gitignore
================================================
# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.

# dependencies
/node_modules
/.pnp
.pnp.js

# testing
/coverage

# production
/build

# misc
.DS_Store
.env
.env.local
.env.development.local
.env.test.local
.env.production.local

npm-debug.log*
yarn-debug.log*
yarn-error.log*

================================================
FILE: README.md
================================================
# Ethers.js by Example
Learn how to use ethers.js from these examples

## Technology Stack & Tools

- Javascript (Writing scripts)
- [Ethers.js](https://docs.ethers.io/v5/) (Blockchain Interaction)
- [Node.js](https://nodejs.org/en/) (To run our scripts and install ethers.js)
- [Infura](https://infura.io/) (Node provider)

## Setting Up
### 1. Clone/Download the Repository

### 2. Install Dependencies:
```
$ npm install
```

## Ethers.js scripts

### 1_accounts.js - Reads balance of ether of wallet address
- Input your infura project ID 
```
$ node examples/1_accounts.js
```

### 2_read_smart_contract.js - Reads the balance of Dai wallet address from the Dai contract
- Input your infura project ID 
```
$ node examples/2_read_smart_contract.js
```

### 3_send_signed_transaction.js - Transfers 0.025 ether from account1 to account2
- Input your infura project ID 
- Input your account1 public key
- Input your account2 public key
- Input your account1 private key
```
$ node examples/3_send_signed_transaction.js
```

### 4_deploy_contract.js - Deploys contract on Kovan testnet by using Factory contract
- Input your infura project ID 
- Input your account private key
```
$ node examples/4_deploy_contract.js
```

### 5_write_contract.js - Transfers entire balance of token of your choosing from account1 to account2 (on Kovan testnet)
- Input your infura project ID 
- Input your account1 public key
- Input your account2 public key
- Input your account1 private key
- Input contract address of the token you want to transfer (You can use the deployed contract address from the previous script)
```
$ node examples/5_write_contract.js
```

### 6_contract_event_stream.js - Queries a block for transfer events
- Input your infura project ID 
```
$ node examples/6_contract_event_stream.js
```

### 7_inspecting_blocks.js - Get transactions from block
- Input your infura project ID 
```
$ node examples/7_inspecting_blocks.js
```

================================================
FILE: examples/1_accounts.js
================================================
const { ethers } = require("ethers");

const INFURA_ID = ''
const provider = new ethers.providers.JsonRpcProvider(`https://mainnet.infura.io/v3/${INFURA_ID}`)

const address = '0x73BCEb1Cd57C711feaC4224D062b0F6ff338501e'

const main = async () => {
    const balance = await provider.getBalance(address)
    console.log(`\nETH Balance of ${address} --> ${ethers.utils.formatEther(balance)} ETH\n`)
}

main()



================================================
FILE: examples/2_read_smart_contract.js
================================================
const { ethers } = require("ethers");

const INFURA_ID = ''
const provider = new ethers.providers.JsonRpcProvider(`https://mainnet.infura.io/v3/${INFURA_ID}`)

const ERC20_ABI = [
    "function name() view returns (string)",
    "function symbol() view returns (string)",
    "function totalSupply() view returns (uint256)",
    "function balanceOf(address) view returns (uint)",
];

const address = '0x6B175474E89094C44Da98b954EedeAC495271d0F' // DAI Contract
const contract = new ethers.Contract(address, ERC20_ABI, provider)

const main = async () => {
    const name = await contract.name()
    const symbol = await contract.symbol()
    const totalSupply = await contract.totalSupply()

    console.log(`\nReading from ${address}\n`)
    console.log(`Name: ${name}`)
    console.log(`Symbol: ${symbol}`)
    console.log(`Total Supply: ${totalSupply}\n`)

    const balance = await contract.balanceOf('0x6c6Bc977E13Df9b0de53b251522280BB72383700')

    console.log(`Balance Returned: ${balance}`)
    console.log(`Balance Formatted: ${ethers.utils.formatEther(balance)}\n`)
}

main()

================================================
FILE: examples/3_send_signed_transaction.js
================================================
const { ethers } = require("ethers");

const INFURA_ID = ''
const provider = new ethers.providers.JsonRpcProvider(`https://kovan.infura.io/v3/${INFURA_ID}`)

const account1 = '' // Your account address 1
const account2 = '' // Your account address 2

const privateKey1 = '' // Private key of account 1
const wallet = new ethers.Wallet(privateKey1, provider)

const main = async () => {
    const senderBalanceBefore = await provider.getBalance(account1)
    const recieverBalanceBefore = await provider.getBalance(account2)

    console.log(`\nSender balance before: ${ethers.utils.formatEther(senderBalanceBefore)}`)
    console.log(`reciever balance before: ${ethers.utils.formatEther(recieverBalanceBefore)}\n`)

    const tx = await wallet.sendTransaction({
        to: account2,
        value: ethers.utils.parseEther("0.025")
    })

    await tx.wait()
    console.log(tx)

    const senderBalanceAfter = await provider.getBalance(account1)
    const recieverBalanceAfter = await provider.getBalance(account2)

    console.log(`\nSender balance after: ${ethers.utils.formatEther(senderBalanceAfter)}`)
    console.log(`reciever balance after: ${ethers.utils.formatEther(recieverBalanceAfter)}\n`)
}

main()

================================================
FILE: examples/4_write_contract.js
================================================
const { ethers } = require("ethers");

const INFURA_ID = ''
const provider = new ethers.providers.JsonRpcProvider(`https://kovan.infura.io/v3/${INFURA_ID}`)

const account1 = '' // Your account address 1
const account2 = '' // Your account address 2

const privateKey1 = '' // Private key of account 1
const wallet = new ethers.Wallet(privateKey1, provider)

const ERC20_ABI = [
    "function balanceOf(address) view returns (uint)",
    "function transfer(address to, uint amount) returns (bool)",
];

const address = ''
const contract = new ethers.Contract(address, ERC20_ABI, provider)

const main = async () => {
    const balance = await contract.balanceOf(account1)

    console.log(`\nReading from ${address}\n`)
    console.log(`Balance of sender: ${balance}\n`)

    const contractWithWallet = contract.connect(wallet)

    const tx = await contractWithWallet.transfer(account2, balance)
    await tx.wait()

    console.log(tx)

    const balanceOfSender = await contract.balanceOf(account1)
    const balanceOfReciever = await contract.balanceOf(account2)

    console.log(`\nBalance of sender: ${balanceOfSender}`)
    console.log(`Balance of reciever: ${balanceOfReciever}\n`)
}

main()

================================================
FILE: examples/5_contract_event_stream.js
================================================
const { ethers } = require("ethers");

const INFURA_ID = ''
const provider = new ethers.providers.JsonRpcProvider(`https://mainnet.infura.io/v3/${INFURA_ID}`)

const ERC20_ABI = [
    "function name() view returns (string)",
    "function symbol() view returns (string)",
    "function totalSupply() view returns (uint256)",
    "function balanceOf(address) view returns (uint)",

    "event Transfer(address indexed from, address indexed to, uint amount)"
];

const address = '0x6B175474E89094C44Da98b954EedeAC495271d0F' // DAI Contract
const contract = new ethers.Contract(address, ERC20_ABI, provider)

const main = async () => {
    const block = await provider.getBlockNumber()

    const transferEvents = await contract.queryFilter('Transfer', block - 1, block)
    console.log(transferEvents)
}

main()

================================================
FILE: examples/6_inspecting_blocks.js
================================================
const { ethers } = require("ethers");

const INFURA_ID = ''
const provider = new ethers.providers.JsonRpcProvider(`https://mainnet.infura.io/v3/${INFURA_ID}`)

const main = async () => {
    const block = await provider.getBlockNumber()

    console.log(`\nBlock Number: ${block}\n`)

    const blockInfo = await provider.getBlock(block)

    console.log(blockInfo)

    const { transactions } = await provider.getBlockWithTransactions(block)

    console.log(`\nLogging first transaction in block:\n`)
    console.log(transactions[0])
}

main()

================================================
FILE: package.json
================================================
{
  "name": "ethers_examples",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "ethers": "^5.5.4"
  }
}