如何在Angular中将对象转换为JSON

Question

Found some answers for angularjs like: How to use angular.toJson on a angular controller or scope but not Angular 2 and following.

I'm new to Angular, worked through the tutorial, and now trying to build my first live app. I have a credentials object that has fields username and password. I want to externalize this to JSON to send to my web service. I found this: https://angular.io/api/common/JsonPipe which seems to do what I want, but the example is in HTML and I want to do it in my service, so here's my service:

import { HttpClient, HttpHeaders } from '@angular/common/http';
import { Injectable } from '@angular/core';
import { JsonPipe } from '@angular/common';
import { Observable } from 'rxjs/Observable';
import { of } from 'rxjs/observable/of';

@Injectable()
export class LoginService {
  authToken = ""
  loginUrl = "localhost:8093/login"

  constructor(private http: HttpClient) { }

  login(credentials): Observable<String> {
    var url = this.loginUrl
                + '?payload='
                + (credentials | json)
    return of(url);
  }
}

But I get an error on the line + (credentials | json) saying json is not found, maybe I meant JSON?

Did I?

Answer 1

Just use

JSON.stringify(credentials)

like in plain JavaScript.

The | json | json pipe is only for view binding like

{{credentials | json}}

but not for TypeScript code.