JAVASCRIPT

async await forEach

// Array.prototype.forEach is not designed for asynchronous code.
// Instead use await Promise.all to process all in parallel if the order doesn't matter.
await Promise.all(array.map(async (element) => {
  await someFunction(element);
}))

use await in for each

files.forEach(async (file) => {
    const contents = await fs.readFile(file, 'utf8')
})

async foreach

[1, 2, 3].forEach(async (num) => {  await waitFor(50);  console.log(num);});console.log('Done');

Do not use forEach with async-await

const players = await this.getWinners();

// BAD
await players.forEach(async (player) => {
  await givePrizeToPlayer(player);
});

await sendEmailToAdmin('All prizes awarded');
============================
Ideal way is


for (const player of players) {
  await givePrizeToPlayer(player);
}

Do not use forEach with async-await

const players = await this.getWinners();

// BAD
await players.forEach(async (player) => {
  await givePrizeToPlayer(player);
});

await sendEmailToAdmin('All prizes awarded');

Do not use forEach with async-await

const players = await this.getWinners();

// BAD
await players.forEach(async (player) => {
  await givePrizeToPlayer(player);
});

await sendEmailToAdmin('All prizes awarded');

await asyc foreach

Array.prototype.forEachAsync = async function (fn) {
    for (let t of this) { await fn(t) }
}

Array.prototype.forEachAsyncParallel = async function (fn) {
    await Promise.all(this.map(fn));
}

Do not use forEach with async-await

const players = await this.getWinners();

// BAD
await players.forEach(async (player) => {
  await givePrizeToPlayer(player);
});

await sendEmailToAdmin('All prizes awarded');

Do not use forEach with async-await

const players = await this.getWinners();

// BAD
await players.forEach(async (player) => {
  await givePrizeToPlayer(player);
});

await sendEmailToAdmin('All prizes awarded');

Do not use forEach with async-await

const players = await this.getWinners();

// BAD
await players.forEach(async (player) => {
  await givePrizeToPlayer(player);
});

await sendEmailToAdmin('All prizes awarded');

Do not use forEach with async-await

const players = await this.getWinners();

// BAD
await players.forEach(async (player) => {
  await givePrizeToPlayer(player);
});

await sendEmailToAdmin('All prizes awarded');

foreach async not working

async function printFiles () {
  const files = await getFilePaths();

  for (const file of files) {
    const contents = await fs.readFile(file, 'utf8');
    console.log(contents);
  }
}

js await in foreach

// Javascript will proceed to call the code that comes AFTER the forEach loop, 
// and then execute the code within the loop. This is because forEach is not 
// async-aware. YOU CANNOT USE AWAIT IN FOREACH. Use a regular for loop instead.

Do not use forEach with async-await

const players = await this.getWinners();

// BAD
await players.forEach(async (player) => {
  await givePrizeToPlayer(player);
});

await sendEmailToAdmin('All prizes awarded');