check-outdated-npm-packages.js

// @ts-check
'use strict'

const { join } = require('path')
const { readFile } = require('fs')
const { promisify } = require('util')

const https = require('https')

const readFileAsync = promisify(readFile)

/**
 *
 * @param {string} url
 * @param {(err: Error|null, data: string|null) => any} callback
 */
const __request = (url, callback) => https.get(
  url,
  { timeout: 1000 },
  res => {
    let data = ''

    // A chunk of data has been recieved.
    res.on('data', chunk => { data += chunk })

    // The whole response has been received.
    res.on('end', () => callback(null, data))
  }
).on('error', err => callback(err, null))

const requestAsync = promisify(__request)

/**
 * @param {string} packageName
 *
 * @returns {Promise<{ 'dist-tags': { latest: string } }>}
 */
const request = async packageName => {
  const plainResult = await requestAsync(`https://registry.npmjs.org/${packageName}`)
  const result = JSON.parse(plainResult)

  return result
}

/**
 * @param {[string, string]} dependencyEntry
 *
 * @returns {Promise<{ [x: string]: string }>}
 */
const checkLatestPackageInRegistry = async dependencyEntry => {
  const [dependency] = dependencyEntry
  const response = await request(dependency)

  return {
    [dependency]: `^${response['dist-tags'].latest}`
  }
}

/**
 * @param {{ [x: string]: string }} dependencies
 *
 * @returns {Promise<{ [x: string]: string }>}
 */
const checkUpdate = async dependencies => (await Promise.all(
  Object.entries(dependencies || {}).map(checkLatestPackageInRegistry)
)).reduce(
  (accummulator, current) => Object.assign({}, accummulator, current), // reducer
  {} // initial value
)

;(async () => {
  try {
    const packageJsonFilePath = join(__dirname, 'package.json')
    const packageJsonContent = await readFileAsync(packageJsonFilePath, 'utf-8')
    /**
     * @type {{ dependencies: { [x: string]: string }, devDependencies: { [x: string]: string } }}
     */
    const { dependencies, devDependencies } = JSON.parse(packageJsonContent)

    const [newDependencies, newDevDependencies] = await Promise.all([
      checkUpdate(dependencies),
      checkUpdate(devDependencies)
    ])

    console.log(
      JSON.stringify({
        dependencies: newDependencies,
        devDependencies: newDevDependencies
      },
      undefined,
      2)
    )
  } catch (error) {
    console.error('Caught an error!')
    console.error(error)
    process.exit(1)
  }
})()