how to resolve array promise and then call the other method

Question

function resolveThisFirst() {
  let newArr = [];
  for (let i = 0; i < 5; i++) {
    setTimeout(() => {
      newArr.push(i);
    }, 2000);
  }

  return Promise.all(newArr);
}

function afterThis() {
  console.log("Call this first after array resolve value");
}

resolveThisFirst()
  .then(afterThis)
  .catch((err) => console.log(err));

I am trying to resolve the array value first then call afterThis function. how can we get this function work.

Thank You

Answer 1

You need to push promises to array, here you were just adding numbers.

function getPromise(time) {
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve(`I have resolved in ${time} ms`);
        }, time);
    });
}

function resolveThisFirst() {
    let newArr = [];
    for (let i = 0; i < 5; i++) {
        newArr.push(getPromise(i * 1000));
    }
    console.log(
        `Promises are ready at ${new Date()} but they will take some time to resolve`
    );
    return Promise.all(newArr);
}

function afterThis() {
    console.log('Call this first after array resolve value');
}

resolveThisFirst()
    .then((data) => {
        console.log(`Promises resolved at ${new Date()}`);
        afterThis();
    })
    .catch((err) => console.log(err));