javascript promise all

var p1 = Promise.resolve(3);
var p2 = 1337;
var p3 = new Promise((resolve, reject) => {
  setTimeout(resolve, 100, "foo");
}); 

Promise.all([p1, p2, p3]).then(values => { 
  console.log(values); // [3, 1337, "foo"] 
});

Promise.all([Promise1, Promise2, Promise3])
 .then(result) => {
   console.log(result)
 })
 .catch(error => console.log(`Error in promises ${error}`))

var p1 = new Promise((resolve, reject) => { 
  setTimeout(resolve, 1000, "one"); 
}); 
var p2 = new Promise((resolve, reject) => { 
  setTimeout(resolve, 2000, "two"); 
});
var p3 = new Promise((resolve, reject) => {
  setTimeout(resolve, 3000, "three");
});
var p4 = new Promise((resolve, reject) => {
  setTimeout(resolve, 4000, "four");
});
var p5 = new Promise((resolve, reject) => {
  reject("reject");
});

Promise.all([p1, p2, p3, p4, p5]).then(values => { 
  console.log(values);
}, reason => {
  console.log(reason)
});

//From console:
//"reject"

// Evenly, it's possible to use .catch
Promise.all([p1, p2, p3, p4, p5]).then(values => { 
  console.log(values);
}).catch(reason => { 
  console.log(reason)
});

//From console: 
//"reject"

const promise1 = Promise.resolve(3);
const promise2 = 42;
const promise3 = new Promise(function(resolve, reject) {
  setTimeout(resolve, 100, 'foo');
});

Promise.all([promise1, promise2, promise3]).then(function(values) {
  console.log(values);
});
// expected output: Array [3, 42, "foo"]

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}`))
view raw

// 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.
timeOut(1000)
 .then(result => console.log(result)) // Completed in 1000

// Promise.all
Promise.all([timeOut(1000), timeOut(2000)])
 .then(result => console.log(result)) // ["Completed in 1000", "Completed in 2000"]

// 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)
  })
}

const durations = [1000, 2000, 3000]

const promises = []

durations.map((duration) => {
  promises.push(timeOut(duration)) 
})

// We are passing an array of pending promises to Promise.all
Promise.all(promises)
.then(response => console.log(response)) // Promise.all cannot be resolved, as one of the promises passed got rejected.
.catch(error => console.log(`Error in executing ${error}`)) // Promise.all throws an error.