Angular 4错误:类型'()=> any'中缺少属性'includes'

Question

我在使用angular 4和observable时遇到错误.

/ Users//backend/src/app/app.component.ts(15,55):输入'()=> any'不能赋值为'State []'./ Users / /backend/src/app/app.component.ts(15,55):输入'()=> any'不能赋值为'State []'.类型'()=>任何'中缺少属性'includes'.

我究竟做错了什么

我的模特

export class State {
  id: number;
  state: string;
  code: string;
}

我的服务

import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/do';
import 'rxjs/add/operator/toPromise';

import {environment} from '../../../environments/environment';

@Injectable()

export class StateService {
  private baseUrl: string = environment.baseUrl;

  constructor( private http: Http) {}

  /**
   * Get all States
   */
  GetStates() {
   return this.http.get(this.baseUrl + 'v1/states')
      .map((res: Response) => res.json);
     // .do( data => console.log(data));
  }
}

我的组件

import { Component, OnInit } from '@angular/core';
import {StateService} from './shared/services/state.service';
import {State} from './shared/models/state';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styles: []
})
export class AppComponent implements OnInit {
   states: State[] ;
  constructor(private stateService: StateService) {}

  ngOnInit() {
    this.stateService.GetStates().subscribe(states => this.states = states );
  }
}

App.Module

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { HttpModule } from '@angular/http';
import 'rxjs/add/operator/map';

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { StateService } from './shared/services/state.service';
@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule,
    AppRoutingModule
  ],
  providers: [
    StateService
  ],
  bootstrap: [AppComponent]
})
export class AppModule { }

Answer 1

有两个问题.

首先,您不是在调用json响应,而只是引用该方法.您需要更改res.json为res.json():

.map((res: Response) => res.json());

其次,您没有声明订阅结果的类型.您应该明确指定结果的类型:

this.stateService.GetStates().subscribe((states: State[]) => this.states = states);

由于您订阅的参数是类型any,除非您像上面一样预先指定类型,或者在赋值之前将其强制转换,否则typescript编译器会通知您类型无效.