Question

bbb(){
    return new Promise((resolve, reject) => {
      this.http.get(this.url).subscribe(data => {
          resolve(data)
        },
         error => {
          reject(error);
        },
      );
    });
  }

ngAfterContentInit(){
    console.log(//THIS LINE
      this.bbb().then(son => {
      return son;
    }));
  }

-此行-在控制台中返回ZoneAwarePromise。我如何退还儿子的价值？

Answer 1

更好的做法是使用Observable：

import { catchError } from 'rxjs/operators';
import { throwError } from 'rxjs';

bbb() {
 return this.http.get(this.url)
   .pipe(
     catchError(err => {
       console.log('err', err);
       return throwError('Something bad happened; please try again later.');
     });
}

然后，只需订阅bbb：

import { Subscription } from 'rxjs';

testSubscription: Subscription;

ngAfterContentInit() {
    this.testSubscription = this.bbb()
      .subscribe(son => {
        console.log('son', son); // here you get the result
      });
}

别忘了unsubscribe：

ngOnDestroy() {
  this.testSubscription.unsubscribe();
}

如果您仍然想使用Promise：

bbb() {
  return this.http.get(this.url).toPromise();
}

要获取bbb的结果：

ngAfterContentInit() {
   this.bbb()
     .then(son => {
       console.log('son', son); // here you get the result
     })
     .catch(err => {
       console.log(err);
     });
}

Angular Promise .then（）返回值

1 个答案: