NullInjectorError: No provider for t! NullInjectorError: StaticInjectorError(ba)[Cw -> t]:

Question

当我运行我的 Angular 8 应用程序的产品构建时，我在控制台中收到此错误。构建运行很好，我已经在我的提供商中包含了所有服务。

我已经运行执行了以下命令，但没有收到任何错误。 ng build --prod --optimization=false 有什么方法可以判断失败的原因吗？即使我注释掉所有提供者（预计构建失败），我仍然没有收到任何错误。

请让我知道我 can/should 提供了哪些其他信息来帮助您。谢谢！

错误信息：

app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';

import { HttpClientModule, HTTP_INTERCEPTORS, HttpClient } from '@angular/common/http';
import { RouterModule } from '@angular/router';
import { AppComponent } from './app.component';
import { HomeComponent } from './home/home.component';
import { NavMenuComponent } from './nav-menu/nav-menu.component';

//a bunch more components...

import { AccountModule } from './account/account.module';
import { AccountRoutingModule } from './account/account.routing.module';
import { AuthGuard } from './helpers/auth.guard';
import { ErrorInterceptor } from './helpers/error.interceptor';
import { JwtInterceptor } from './helpers/jwt.interceptor';

import { TemplateService } from './services/template.service';
import { ExerciseService } from './services/exercise.service';
import { ExamService } from './services/exam.service';
import { AuthService } from './services/auth.service';
import { FeatureService } from './services/feature.service';
import { RoleService } from './services/role.service';
import { UserService } from './services/user.service';

@NgModule({
  declarations: [
    AppComponent,
    NavMenuComponent,
    HomeComponent,

  ],
  imports: [
    BrowserModule.withServerTransition({ appId: 'ng-cli-universal' }),
    HttpClientModule,
    FormsModule,
    ReactiveFormsModule,
    BrowserAnimationsModule,
    AccountModule,
    AccountRoutingModule,
    RouterModule.forRoot([
      { path: '', component: HomeComponent, canActivate: [AuthGuard] },
      //all routes left out for brevity
    ])
  ],
  //entryComponents: [NewTemplateModal, NewExerciseModal, AddFeaturesModal, SaveSuccessComponent, ErrorComponent],
  providers: [    
    AuthService,
    ExamService,
    ExerciseService,
    FeatureService,
    RoleService,
    TemplateService,
    UserService,
    HttpClient,
    { provide: HTTP_INTERCEPTORS, useClass: ErrorInterceptor, multi: true },
    { provide: HTTP_INTERCEPTORS, useClass: JwtInterceptor, multi: true },
  ],
  bootstrap: [AppComponent]
})
export class AppModule { }

构建：

Answer 1

原来是个蠢货...

在我的一个组件中，我有 providers:[]。一旦我完全删除它，它就开始工作了。

希望这可以帮助到其他人！

Answer 2

@Injectable({
    providedIn: 'root'
})
export interface Cars {
    number: number;
    model: string;
    owner: string;
    ownerPhone: string;
}

对我来说，错误是我的@decorator 在服务中无效

NullInjectorError: No provider for t! NullInjectorError: StaticInjectorError(ba)[Cw -> t]:

NullInjectorError: No provider for t! NullInjectorError: StaticInjectorError(ba)[Cw -> t]:

typescript

angular-providers

angular

ng-build