SYMBOL INDEX (6 symbols across 3 files)

FILE: app.js
  constant PORT (line 4) | const PORT = process.env.PORT || 5000

FILE: client/src/App.js
  function App (line 64) | function App() {

FILE: client/src/serviceWorker.js
  function register (line 23) | function register(config) {
  function registerValidSW (line 57) | function registerValidSW(swUrl, config) {
  function checkValidServiceWorker (line 101) | function checkValidServiceWorker(swUrl, config) {
  function unregister (line 131) | function unregister() {