Run array of promises and stop on first failure

promise-chain-failed-first.js

'use strict'

global.state = {
  time: null,
  user: null,
  photo: null,
  book: null
}

const { getTime, getUser, getPhoto, getBook } = require('./promise_modules')

let asyncArray = [getTime, getUser, getPhoto, getBook]

asyncArray.reduce((cur, next) => {
    return cur.then(() => next())
  }, Promise.resolve())
  .then(() => {
      console.log('all executed')
      console.log('Chain ended')
      console.log(JSON.stringify(state, null, 4))
  })
  .catch((err) => {
    console.error(err + '')
    console.log('Chain ended')
    console.log(JSON.stringify(state, null, 4))
  })

/*
Result:

Chain ended
{
    "time": {
        "epoch": 1514967283,
        "slang_date": "today",
        "slang_time": "now",
        "iso8601": "2018-01-03T08:14:43Z",
        "rfc2822": "Wed, 03 Jan 2018 08:14:43 GMT",
        "rfc3339": "2018-01-03T08:14:43.00Z"
    },
    "user": {
        "error": "Error: Protocol \"http:\" not supported. Expected \"https:\""
    },
    "photo": null,
    "book": null
}
*/

promise-modules.js

'use strict'

const https = require('https'), http = require('http')

let getTime = () => {

    return new Promise((resolve, reject) => {

        try {

            let url = 'https://now.httpbin.org/when/' + (new Date()).getTime()

            https.get(url, (res) => {

                let body = '';

                res.on('data', (chunk) => { body += chunk })

                res.on('end', () => {
                    let response = JSON.parse(body)
                    state.time = response.timestamp
                    resolve()
                })

            }).on('error', (e) => {
                  return reject(e + '')
            })

        } catch (e) {
            return reject(e + '')
        }
    })
}

let getUser = () => {

    return new Promise((resolve, reject) => {

        try {

            let url = 'http://jsonplaceholder.typicode.com/users/8'

            https.get(url, (res) => {

                let body = '';

                res.on('data', (chunk) => { body += chunk })

                res.on('end', () => {
                    let response = JSON.parse(body)
                    state.user = response
                    resolve()
                })

            }).on('error', (e) => {
                  return reject(e + '')
            })

        } catch (e) {
            state.user = { error: e + '' }
            return reject(e + '')
        }
    })
}

let getPhoto = () => {

    return new Promise((resolve, reject) => {

        try {

            let url = 'https://jsonplaceholder.typicode.com/photos/1'

            https.get(url, (res) => {

                let body = '';

                res.on('data', (chunk) => { body += chunk })

                res.on('end', () => {
                    let response = JSON.parse(body)
                    state.photo = response
                    resolve()
                })

            }).on('error', (e) => {
                  return reject(e + '')
            })

        } catch (e) {
            return reject(e + '')
        }
    })
}

let getBook = () => {

    return new Promise((resolve, reject) => {

        try {

            let url = 'https://fakerestapi.azurewebsites.net/api/Booksa/a'

            https.get(url, (res) => {

                let body = '';

                res.on('data', (chunk) => { body += chunk })

                res.on('end', () => {
                    let response = JSON.parse(body)
                    if (res.statusCode === 200) { state.book = response }
                    else if (res.statusCode >= 400 && res.statusCode < 500) { state.book = { status: res.statusCode, error: response } }
                    resolve()
                })

            }).on('error', (e) => {
                  state.book = { error: e + '' }
                  return reject(e + '')
            })

        } catch (e) {
            state.book = { error: e + '' }
            return reject(e + '')
        }
    })
}

module.exports = {
  getTime: getTime,
  getUser: getUser,
  getPhoto: getPhoto,
  getBook: getBook
}