javascript - 确保一组 deferred.then 回调完成

Question

我正在使用 Dojo 1.10，它附带了 Deferred 和 Promise API。所以场景如下:

 var deferred_1 = new Deferred();
 deferred_1 .then(function(value){
  // do something
  return something;
 })

 var deferred_2 = new Deferred();
 deferred_2.then(function(value){
  // do something
  return something;
 })

var completeFunc = function(value){
    console.log("done");
}

//run completeFunc after completion of both deferred_1.then and 
deferred_2.then

如何确保在运行另一个函数之前完成 deferred_1.then 和 deferred_2.then 中的两个延迟对象回调函数。

Answer 1

使用 Promise.all 创建一个 Promise，该 Promise 仅在您传递给它的所有 Promise 都得到解析后才解析。请注意，您必须保存对新 promise 的引用:

const deferred_1 = new Deferred();
const d1 = deferred_1.then(function(value) {
  // do something
  return something;
});
const deferred_2 = new Deferred();
const d2 = deferred_2.then(function(value) {
  // do something
  return something;
})
const completeFunc = function(value) {
  console.log("done");
}
Promise.all([d1, d2]).then(completeFunc);