Http Get Response Updates HTML but giving undefine

问题:

When I am updating my Html with the response Obj using HttpClient it updates the values but gives errors. kindly Help!

File Name - auth-service.ts

import { any } from 'codelyzer/util/function';
import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';

@Injectable()
export class AuthService {

  constructor(private httpClient: HttpClient) { }
  get() {
    return this.httpClient.get<any>('/capi/v2/users/me', {
      observe: 'body',
      responseType: 'json'
    });
  }
};

File Name - dashboard.component.ts

import { AuthService } from './../../services/api/auth-service';

import { Component, Injectable, OnInit } from '@angular/core';

@Component({
    selector: 'app-dashboard',
    templateUrl: './dashboard.component.html'
})

@Injectable()
export class DashBoardComponent implements OnInit {
    user;
    constructor(private authService: AuthService) {};

    ngOnInit() {
         this.authService.get()
        .subscribe(
          (response) => {
              this.user = response;
          }
        );
    }
}

The Response Obj is -

{

"firstName": "xyz",
"lastName": "abc",
"active": true

}

File Name - dashboard.component.html

<div class="container-fluid text-center">
    <h1 class="bold m-t m-b-xs">Hey there!</h1>
    <h3 class="m-b">How are you doing today?</h3>


    {{ user.active }}

    <div class="block clear m-a">&nbsp;</div>

    <div class="row m-t p-t">
      <div class="col-xs-12">
      </div>
    </div>
</div>

Error in console

回答1:

You can simply update {{ user.active }} to include a ?. i.e.:

{{ user?.active }}

Your error is likely because Angular attempts to evaluate user.active before the get request completes.

This is known as the safe navigation operator:

The Angular safe navigation operator (?.) is a fluent and convenient way to guard against null and undefined values in property paths.

You could instead use ngIf to avoid rendering your container until the data is retrieved. i.e.:

<div class="container-fluid text-center" *ngIf="user">

回答2:

You need to use map function to return response to component. Replace this code with you service get.

get() {
  return this.httpClient.get<any>('/capi/v2/users/me')
    .map((resp) => resp)
    .catch((error) => error);
}