Question

我是Angular的新手，

尝试创建将从MongoDB数据库中获取记录的函数，但是出现问题。 API URL工作正常。

文件：data.services.spec.ts

import { Injectable } from '@angular/core';


import { Http, Headers, RequestOptions } from '@angular/http';
import 'rxjs/add/operator/map';
import 'rxjs/Rx';

@Injectable()

export class DataService {

  result:any;

  constructor(private _http: Http) { }

  getUsers() {
    return this._http.get("/api/users")
          .map(result => this.result = result.json().data);
  }

}

文件：app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppComponent } from './app.component';

// Import the Http Module and our Data Service
import { HttpModule } from '@angular/http';
import { DataService } from './data.service';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    HttpModule
  ],
  providers: [ DataService ],
  bootstrap: [AppComponent]
})
export class AppModule { }

文件：app.component.ts

import { Component } from '@angular/core';

// Import the DataService
import { DataService } from './data.service';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'mean';

    // Define a users property to hold our user data
    users: Array<any>;
    // Create an instance of the DataService through dependency injection
    constructor(private _dataService: DataService) { 
      // Access the Data Service's getUsers() method we defined
      this._dataService.getUsers()
          .subscribe(res => this.users = res);
    }
}

错误在这里this._dataService.getUsers()。任何建议将不胜感激。

Answer 1

您应该在 data.services.ts 中写服务，而不要在 data.services.spec.ts

中写服务

在data.services.ts

中

import { Injectable } from '@angular/core';
import { Observable} from 'rxjs';


import { Http, Headers, RequestOptions } from '@angular/http';
import 'rxjs/add/operator/map';
import 'rxjs/Rx';

@Injectable()

export class DataService {

  result:any;

  constructor(private _http: Http) { }

  getUsers(): Observable<any> {
    return this._http.get("/api/users")
          .map(result => this.result = result.json().data);
  }

}

在组件中：

import { DataService } from './data.service';

Answer 2

在下面的链接中找到示例

stackblitz

您使用的是data.services.spec.ts而不是data.services.ts，spec.ts扩展用于测试希望对您有帮助

src / app / app.component.ts（19,25）中的错误：错误TS2339：类型“ Dataservice”上不存在属性“ getUsers”

2 个答案: