等待函数完成后再返回承诺

Question

someFunction() {
  if (array.length > 0) {
    return new Promise((resolve, reject) => {
      array.map(item => {
        AXIOS.postItem(item).catch(err => {reject('error')});
      });
      resolve('resolve');
    });
  }
}

mainFunction() {
  Promise.all([this.someFunction()]).then(() => {
    this.invokeTheRest();
  )}
}

In my case, the some function always returns resolve , even before the AXIOS.postItem() is executed or caught.

How could i wait for the AXIOS.postItem() to execute? And if there is error caught in catch how could i NOT proceed to this.invokeTheRest() ?

Answer 1

Change the body of someFunction to just:

someFunction () {
    return array.map(item => AXIOS.postItem(item));
}

So that it returns an array of Promises that can be used with Promise.all .

Answer 2

Having someFunction return an array of promises I would say is a coding anti-pattern.

The way I would go is to return the Promise.all from someFunction, this will then make someFunction into a Promise, that you can then use just like any other promise.

eg.

someFunction() {
  return Promise.all(
    array.map(item => AXIOS.postItem(item)));
}

mainFunction() {
  this.someFunction().then(() => {
    this.invokeTheRest();
  });
}