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@darul75 darul75/async.js forked from bschwartz757/async.js
Created Mar 14, 2019

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Async/await function to fetch data from multiple URLs in parallel
/* Client side, works in Chrome 55 and Firefox 52 without transpilation */
//https://blogs.msdn.microsoft.com/typescript/2016/11/08/typescript-2-1-rc-better-inference-async-functions-and-more/
async function fetchURLs() {
try {
// Promise.all() lets us coalesce multiple promises into a single super-promise
var data = await Promise.all([
/* Alternatively store each in an array */
// var [x, y, z] = await Promise.all([
// parse results as json; fetch data response has several reader methods available:
//.arrayBuffer()
//.blob()
//.formData()
//.json()
//.text()
fetch('https://jsonplaceholder.typicode.com/posts').then((response) => response.json()),// parse each response as json
fetch('https://jsonplaceholder.typicode.com/albums').then((response) => response.json()),
fetch('https://jsonplaceholder.typicode.com/users').then((response) => response.json())
]);
for (var i of data) {
console.log(`RESPONSE ITEM \n`);
for (var obj of i) {
console.log(obj);
//logger utility method, logs output to screen
console.log(obj);
}
}
} catch (error) {
console.log(error);
}
}
/* NodeJS version */
//uses the `request` package which makes working with Node's native http methods easier
const request = require('request');
var requestAsync = function(url) {
return new Promise((resolve, reject) => {
var req = request(url, (err, response, body) => {
if (err) return reject(err, response, body);
resolve(JSON.parse(body));
});
});
};
const urls = [
'https://jsonplaceholder.typicode.com/posts',
'https://jsonplaceholder.typicode.com/albums',
'https://jsonplaceholder.typicode.com/users'
];
/* Works as of Node 7.6 */
var getParallel = async function() {
//transform requests into Promises, await all
try {
var data = await Promise.all(urls.map(requestAsync));
} catch (err) {
console.error(err);
}
console.log(data);
}
getParallel();
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