srebalaji

const durations = [1000, 2000, 3000]

promises = durations.map((duration) => {
  return timeOut(duration).catch(e => e) // Handling the error for each promise.
})

Promise.all(promises)
  .then(response => console.log(response)) // ["Completed in 1000", "Rejected in 2000", "Completed in 3000"]
  .catch(error => console.log(`Error in executing ${error}`))

srebalaji

// Async function to send mail to a list of users.
const sendMailForUsers = async (users) => {
  const usersLength = users.length
  
  for (let i = 0; i < usersLength; i += 100) { 
    const requests = users.slice(i, i + 100).map((user) => { // The batch size is 100. We are processing in a set of 100 users.
      return triggerMailForUser(user) // Async function to send the mail.
       .catch(e => console.log(`Error in sending email for ${user} - ${e}`)) // Catch the error if something goes wrong. So that it won't block the loop.
    })
    

srebalaji

// A simple promise that resolves after a given time
const timeOut = (t) => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (t === 2000) {
        reject(`Rejected in ${t}`)
      } else {
        resolve(`Completed in ${t}`)
      }
    }, t)

srebalaji

// A simple promise that resolves after a given time
const timeOut = (t) => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve(`Completed in ${t}`)
    }, t)
  })
}

const durations = [1000, 2000, 3000]

srebalaji

// A simple promise that resolves after a given time
const timeOut = (t) => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve(`Completed in ${t}`)
    }, t)
  })
}

// Resolving a normal promise.

srebalaji

set number                                      
set noet ci pi sts=0 sw=4 ts=4
set cursorline
set showcmd
filetype indent on
set wildmenu
set lazyredraw
set showmatch
set incsearch
set hlsearch