Modify json with input from gulp-hashsum

gulp-modify-json.js

const { src } = require('gulp')
const fs = require('fs')
const path = require('path')
const through = require('through2')
const hashsum = require('gulp-hashsum')

const modifyJson = ({ fileName, src, property }) => through.obj((file, _, cb) => {
  const { name } = path.parse(file.path)
  if (name !== fileName) return cb(null, file)

  const pathToJson = path.resolve(__dirname, src)
  if (!fs.existsSync(pathToJson)) {
    return cb(new Error(`${src} doesn't exist.`), file)
  }
  const json = JSON.parse(fs.readFileSync(pathToJson, 'utf8'))

  const content = JSON.parse(file.contents)
  if (typeof json[property] === 'undefined') console.warn(`${src} doesn't has any property named '${property}' A new one will be created.`)
  json[property] = content
  fs.writeFileSync(pathToJson, JSON.stringify(json))

  return cb(null, file)
})

exports.modifyJson = () =>
  src(['app/**/*.js'])
  .pipe(hashsum({
    stream: true,
    json: true,
  }))
  .pipe(modifyJson({
    fileName: 'SHA1SUMS',
    src: './test.json',
    property: 'hashTable',
  }))