New features in JavaScript 2021

// Without optional chaining
let userAdmin = undefined;
if (payload.access && payload.access.admin && payload.access.admin[0]) {
  userAdmin = payload.access.admin[0].user;
}// With optional chaining
const userAdmin = payload.access?.admin?[0]?.user;

const arr = ['a', 'b', ['c', 'd']];
const flattened = arr.flat();console.log(flattened);    
// Result: ["a", "b", "c", "d"]

const myArray = [['one', 1], ['two', 2], ['three', 3]];
const obj = Object.fromEntries(myArray);console.log(obj);    
// Result: {one: 1, two: 2, three: 3}

ES2021

String.prototype.replaceAll

String.prototype.replaceAll() replaces all occurrences of a string with another string value.

// You can break the digits in any way
const BIGNUMBER = 1234_5678_9_0;  // 1234567890// Even after the comma/period
const PI = 3.1415_9265_3589;     // 3.141592653589// However, ending or beginning with an underscore will return an error!const BAD_PI = 3.14_15_;          // SyntaxError
const NO_MILLION = _1_000_000;    // ReferenceError

Comments

for loop in javascript - promise - .eslintrc for "for of"

the vast majority of cases map , forEach , find etc. can be used. async function printFiles () { const files = await getFilePaths(); await Promise.all(files. map (async (file) => { const contents = await fs.readFile(file, 'utf8') console.log(contents) })); } const inventory = [ { name : 'apples' , quantity : 2 } , { name : 'bananas' , quantity : 0 } , { name : 'cherries' , quantity : 5 } ] ; const result = inventory . find ( ( { name } ) => name === 'cherries' ) ; function getFirstMatching(array) { for (let item of array) { const result = heavyTransform(item); if (result) { return result; } } } Specifically this shuts down the whole no-restricted-syntax. If you want to cherry-pick, here is the current definition: 'no-restricted-syntax' : [ 'error' , { selector : 'ForInStatement' , message...

fs.writeFile - permission issue on GCP (Google Cloud Run)

error on this: fs . writeFile ( fileName , pdfBytes , err => { if ( err ) { console . log ( err . message ) reject ( err . message ) } else resolve ( fileName ) }) #1 It looks like when deployed into Cloud Run it also requires the extra permission "Service Account Token Creator" to run getSignedUrl . Locally for some reason this role is not required. #2 Only the directory /tmp is writable in Cloud Run. So, change the default write location to write into this directory. However, you have to be aware of 2 things: Cloud Run is stateless, that means when a new instance is created, the container start from scratch, with an empty /tmp directory /tmp directory is an in-memory file system. The maximum allowed memory on Cloud Run is 2Gb, your app memory footprint included. In addition of your file and Airflow, not sure that you will have a lot of space. A final remark. Cloud Run is active only when it...

add new site to Vagrant Homestead

Homestead.yaml: folders : - map : ~/ freshinup to : / home / vagrant / code sites : - map : smartmotors . local . com to : / home / vagrant / code / smartmotors / public php : "7.3" - map : arbor . test to : / home / vagrant / code / arbor / public php : "7.3" /etc/hosts: 192.168.10.10 arbor.test 192.168.10.10 smartmotors.local.com vagrant up --provision php artisan smartmotors:seed --quickstart

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