Angular 4 Error: No provider for HttpClient

Question

我正在使用 CLI 开始一个新的 angular 项目，并且运行因 HttpClient 错误而成为无提供者。

我已将 HttpClientModule 添加到我的模块导入中，这似乎是这种情况下的常见罪魁祸首。除此之外，在网上找不到很多东西，所以我不确定可能是什么问题。

我的app.module.ts

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

和我的服务

@Injectable()
export class FlexSearchService {


    constructor(private http: HttpClient) {}

    getSavedSearchResult(index: string, queryName: string, query: string ): Observable<any> {
      const url = `${environment.flexUrl}/${index}/search`;
      const item = new SearchQuery({queryName: queryName, variables: {q: query}});
      return this.http.post(url, item);
    }
}

和 ng 版本给出以下输出

@angular/cli: 1.4.2
node: 6.9.4
os: darwin x64
@angular/animations: 4.4.4
@angular/common: 4.4.4
@angular/compiler: 4.4.4
@angular/core: 4.4.4
@angular/forms: 4.4.4
@angular/http: 4.4.4
@angular/platform-browser: 4.4.4
@angular/platform-browser-dynamic: 4.4.4
@angular/router: 4.4.4
@angular/cli: 1.4.2
@angular/compiler-cli: 4.4.4
@angular/language-service: 4.4.4
typescript: 2.3.4

我的 tsconfig

{
  "compileOnSave": false,
  "compilerOptions": {
    "outDir": "./dist/out-tsc",
    "sourceMap": true,
    "declaration": false,
    "moduleResolution": "node",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "target": "es5",
    "typeRoots": [
      "node_modules/@types"
    ],
    "lib": [
      "es2017",
      "dom"
    ]
  }
}

我的测试

import { TestBed, inject } from '@angular/core/testing';
import { HttpClientModule } from '@angular/common/http';
import { FlexSearchService } from './flex-search.service';

describe('FlexSearchService', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [FlexSearchService, HttpClientModule]
    });
  });
  it('should be created', inject([FlexSearchService], (service: FlexSearchService) => {
    expect(service).toBeTruthy();
  }));

非常感谢任何帮助！

Answer 1

在你的测试中

TestBed.configureTestingModule({
      providers: [FlexSearchService, HttpClientModule]
    });

应该是

TestBed.configureTestingModule({
      imports: [HttpClientModule],
      providers: [FlexSearchService]
    });

甚至更好（如果你想模拟请求）：

TestBed.configureTestingModule({
      imports: [HttpClientTestingModule],
      providers: [FlexSearchService]
    });

Answer 2

一种更简单的方法是在全球范围内提供它....将以下内容导入 app.module.ts，如下所示：

import { HttpModule } from '@angular/http'
import { HttpClient, HttpClientModule } from '@angular/common/http';

并在进口申报：

  imports: [
    HttpModule,
    HttpClientModule, ...
]

Answer 3

导入 HttpClientTestingModule。

在你的测试中：

import { HttpClientTestingModule } from '@angular/common/http/testing';

并在测试的 configureTestingModule 中，执行以下操作：

TestBed.configureTestingModule({
    imports: [ HttpClientTestingModule ],
})
.compileComponents();

Answer 4

为此，您必须导入以下内容：

import { HttpClientTestingModule } from '@angular/common/http/testing';

对于测试 configureTestingModule 中的规范文件，请执行以下操作：

TestBed.configureTestingModule({
    imports: [ HttpClientTestingModule ],
})
.compileComponents();

Answer 5

我在尝试使用 npm link.

在我的项目中本地 link 我的 angular 库时注意到了这个问题

从存储库下载库解决了我的问题。

Angular 4 Error: No provider for HttpClient

Angular 4 Error: No provider for HttpClient

angular

angular-httpclient