Find unused action types in Redux stores. no eslint rule for that :| easy to miss during actionTypes refactoring

unusedActionTypes.js

#!/usr/bin/env node

const fs = require('fs')

const isWin = process.platform === "win32";
const findCmd = isWin ? 'dir /s *store.js' : 'find src -name "*store.js"'

const exec = require('child_process').exec
const findStores = () => new Promise((resolve, reject) => {
  exec(
    findCmd,
    function (error, stdout, stderr) {
      resolve(stdout)
      if (error !== null) {
        console.log('exec error: ' + error)
        console.log('stderr: ' + stderr)
        reject(error)
      }
    }
  )}
)

const cleanLineFromActionType = line => {
  const pattern = /^\s*([\w_]+):\s/
  const match = line.match(pattern)
  return match ? match[1] : ''
}

const getActionTypes = store => {
  const pattern = /const actionTypes = {((?:\n|\s.*)*)/mg
  const match = store.match(pattern)
  if(!match) {
    return []
  }

  const lines = match[0].split('\n')
  const types = lines.map(cleanLineFromActionType).filter(x => !!x)
  return types
}

const getReducer = store => {
  const pattern = /export const reducer = \(.+\n((?:\n|\s.*)*)/mg
  const match = store.match(pattern)
  if(!match) {
    return ''
  }

  return match[0]
}

const finder = (action, reducer) => {
  const pattern = new RegExp(`case actionTypes.${action}`, "gm")
  const match = reducer.match(pattern)
  return !!match
}

const parseStore = async file => {
  const content = await new Promise((resolve, reject) => {
    fs.readFile(file, 'utf8', function(err, contents) {
      if (err) { 
        console.error(err)
        resolve(null)
       }
      resolve(contents)
    })
  })
  if (!content) {
    return null
  }

  const actionTypes = getActionTypes(content)
  const reducer = getReducer(content)

  const unusedActions = actionTypes.filter(action => !finder(action, reducer)).join(', ')

  return [file, unusedActions]
}

const main = async () => {
  const stores = await findStores()
  const storesList = stores.split('\n')
  const fileUnusedActions = await Promise.all(storesList.map(parseStore))
  const filteredFilesWithUnusedActions = fileUnusedActions.filter(store => store && store[1])
  return filteredFilesWithUnusedActions.map(f => f.join('\n\t')).join('\n\n')
}

main().then(console.log)