Very simple and useful implementation of foreach based on promises for parallel requests. For NodeJS.
Works great in the browser with browserify.
$ npm install promise-foreach
const promiseForeach = require('promise-foreach')
const list = [{
firstName: 'John',
lastName: 'Doe'
}, {
firstName: 'Marie',
lastName: 'Doe'
}]
promiseForeach.each(list,
person => {
return `${person.firstName} ${person.lastName}`
},
(arrResult, person) => {
return {
firstName: person.firstName,
lastName: person.lastName,
fullName: arrResult[0]
}
},
(err, newList) => {
if (err) {
console.error(err)
return ;
}
console.log('newList : ', newList)
})const https = require('https');
const promiseForeach = require('promise-foreach')
const list = [{
firstName: 'John',
lastName: 'Doe',
photo_id: 1
}, {
firstName: 'Marie',
lastName: 'Doe',
photo_id: 2
}]
promiseForeach.each(list,
[
person => {
return `${person.firstName} ${person.lastName}`
},
person => {
return asyncGetPhoto(person.photo_id)
}
],
(arrResult, person) => {
return {
firstName: person.firstName,
lastName: person.lastName,
fullName: arrResult[0],
photo: arrResult[1]
}
},
(err, newList) => {
if (err) {
console.error(err)
return ;
}
console.log('newList : ', newList)
})
function asyncGetPhoto(photo_id) {
return new Promise(function (resolve, reject) {
var request = https.get('https://jsonplaceholder.typicode.com/photos/' + photo_id, function (response) {
var body = []
response.on('data', function (chunk) {
body.push(chunk)
})
response.on('end', function () {
resolve(JSON.parse(body.join('')))
})
})
request.on('error', function (err) {
reject(err)
})
})
}const https = require('https');
const promiseForeach = require('promise-foreach')
const list = [{
firstName: 'John',
lastName: 'Doe',
photo_id: 1,
comment_id: 3
}, {
firstName: 'Marie',
lastName: 'Doe',
photo_id: 2,
comment_id: 4
}]
promiseForeach.each(list,
[
person => {
return `${person.firstName} ${person.lastName}`
},
person => {
return asyncGetPhoto(person.photo_id)
},
person => {
return asyncGetComment(person.comment_id)
}
],
(arrResult, person) => {
return {
firstName: person.firstName,
lastName: person.lastName,
fullName: arrResult[0],
photo: arrResult[1],
comment: arrResult[2]
}
},
(err, newList) => {
if (err) {
console.error(err)
return ;
}
console.log('newList : ', newList)
})
function asyncGetPhoto(photo_id) {
return new Promise(function (resolve, reject) {
var request = https.get('https://jsonplaceholder.typicode.com/photos/' + photo_id, function (response) {
var body = []
response.on('data', function (chunk) {
body.push(chunk)
})
response.on('end', function () {
setTimeout(function () {
resolve(JSON.parse(body.join('')))
}, 1000)
})
})
request.on('error', function (err) {
reject(err)
})
})
}
function asyncGetComment(comment_id) {
return new Promise(function (resolve, reject) {
var request = https.get('https://jsonplaceholder.typicode.com/comments/' + comment_id, function (response) {
var body = []
response.on('data', function (chunk) {
body.push(chunk)
})
response.on('end', function () {
resolve(JSON.parse(body.join('')))
})
})
request.on('error', function (err) {
reject(err)
})
})
}$ browserify -r promise-foreach > modules.js
<script src="modules.js"></script>
<script>
const promiseForeach = require('promise-foreach');
</script>
<script>
const list = [{
firstName: 'John',
lastName: 'Doe',
photo_id: 1
}, {
firstName: 'Marie',
lastName: 'Doe',
photo_id: 2
}]
promiseForeach.each(list,
[
person => {
return `${person.firstName} ${person.lastName}`
},
person => {
return asyncGetPhoto(person.photo_id)
}
],
(arrResult, person) => {
return {
firstName: person.firstName,
lastName: person.lastName,
fullName: arrResult[0],
photo: arrResult[1]
}
},
(err, newList) => {
if (err) {
console.error(err)
return ;
}
console.log('newList : ', newList)
})
function asyncGetPhoto(photo_id){
return new Promise(function(resolve, reject){
var request = new Request('https://jsonplaceholder.typicode.com/photos/' + photo_id,{
method: 'GET'
})
fetch(request).then(function(response){
resolve(response.json())
})
.catch(function(error){
reject(error)
})
})
}
</script>To run the package's test, first install the dependencies, then run npm test:
$ npm install
$ npm test
MIT License