promise all convert the result into an object

Question

I'm using promise.all in my resolver, it works, but now, I don't want an array of promises but an object, but I can't find how to do it.

This is my try:

resolve(route: ActivatedRouteSnapshot): Promise<any> {

  return Promise.all([
    this.service1.getAll(),
    this.service2.getAll(),
    this.service3.getAll()]
      .map((result) => {
        first: result[0],
        second: result[1],
        third: result[2]
      })
  ) 
}

As you can see I want to convert the array into an object with key - value

how can I map the result to get an object instead the array?

Answer 1

您实际上可以在此处使用es6 中的析构。由于您Promise.all(...)将解决与在它三个项目的数组，你可以[first, second, third]作为参数传递给箭头功能和JavaScript将采摘的项目出自己的位置的阵列中，并将它们设为变量与相应的名称（即first，second，而third在这种情况下）。

此外，如果您保持变量名称与对象的属性名称相同，您可以使用下面的简写语法来创建对象。

resolve(route: ActivatedRouteSnapshot): Promise<any> {
    return Promise.all([
        this.service1.getAll(),
        this.service2.getAll(),
        this.service3.getAll()
    ]).then(([first, second, third]) => ({ first, second, third }));
}

作为参考，TypeScript 将 中的代码.then(...)转换为以下 es5 JavaScript：

.then(function (_a) {
    var first = _a[0], second = _a[1], third = _a[2];
    return ({ first: first, second: second, third: third });
})

Answer 2

你可以用ES6做到这一点：

const [x,y,z] = ['E','S','6'];
// x = 'E'
// y = 's'
// z = '6'

所以你可以使用相同的Promise.all

const [first, second, third] = await Promise.all([
  this.service1.getAll(),
  this.service2.getAll(),
  this.service3.getAll()
]);

Answer 3

试试这个方法

resolve(route: ActivatedRouteSnapshot): Promise<any> {

 return Promise.all([
this.service1.getAll(),
this.service2.getAll(),
this.service3.getAll()]
  .map((result) => {
    this.allData = Object.assign({},result)
  })
 ) 
} 

我希望这可以帮助你......:)