如何从 5 角订阅中返回承诺 [英] How to return a promise from subscribe in angular 5

问题描述

我想问一下，我们如何从 subscribe 函数返回一个 promise.

I want to ask that how can we return a promise from the subscribe function.

代码如下:

A.ts

makeHttpRequest() {
    return this.http.get('https://example.com/login');
}

B.ts

class B {
    constructor(private a: A) {  
        this.a.makeHttpRequest().subscribe(data => {
            //How to return a promise from here
        });
    }

}

我提供了一个非常抽象的代码级别，如果有人在理解时遇到任何问题，请告诉我.

I have provided a very abstract level of code if someone is facing any issue to understand it please let me know.

推荐答案

我已经开发了上述问题的解决方案:

I have developed the solution of question asked above:

class B {
        constructor(private a: A) {

        return new Promise((resolve,reject)=>{
         this.a.makeHttpRequest().subscribe(data => {
                resolve(true);
      }, (err)=> {
            resolve(false);
        });
  });

    }

}

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