Angular2 rc5> component does not get loaded

Question

I have recently moved to Angular2 RC5 from RC4. Since then I have encountered couple of problems. I'm not sure whether these problems are my because of fault or transitional. My app component looks like this :

import {Component, OnInit} from "@angular/core";
import {SetLocationService} from "./auth/set-location.service";

@Component({
  selector : "my-app",
  template: `
  <app-header></app-header>
    <router-outlet></router-outlet>
  <app-footer></app-footer>
  `
})

export class AppComponent implements OnInit{
  constructor(
    private _setLocationService : SetLocationService
  ){}

  ngOnInit() {
    this._setLocationService.setLocation();
  }
}

routing :

import {Routes, RouterModule} from '@angular/router';
import {SearchBoxComponent} from "./search/searchBox.component";
import {SearchResultComponent} from "./search/search-result.component";
import {LoginComponent} from "./auth/login.component";
import {SignupComponent} from "./auth/signup.component";
import {LogoutComponent} from "./auth/logout.component";
import {RecoverPasswordComponent} from "./auth/recover-password.component";
import {ProfileComponent} from "./auth/profile.component"
import {AccountComponent} from "./auth/account.component"

const appRoutes: Routes = [
  {path : '',  component: SearchBoxComponent},
  {path : 'login',  component: LoginComponent},
  {path : 'signup', component: SignupComponent},
  {path : 'logout', component: LogoutComponent},
  {path : 'profile', component: ProfileComponent},
  {path : 'account', component: AccountComponent},
  {path : 'user/:uname', component: SearchBoxComponent},
  {path : 'recover-password', component: RecoverPasswordComponent},
  {path : 'search/:params', component: SearchResultComponent},
  {path : '**', component : SearchBoxComponent}
];

export const routing = RouterModule.forRoot(appRoutes);

app module :

// @Modules -> Modules
import {BrowserModule} from '@angular/platform-browser';
import {FormsModule} from '@angular/forms';
import {HttpModule} from '@angular/http';
import {LocationStrategy, HashLocationStrategy} from '@angular/common';
import {NgModule} from '@angular/core';
// import {RouterModule} from '@angular/router';

// @Routes -> routes
import {routing} from "./app.routes";

// @Components - > Components
import {AccountComponent} from "./auth/account.component";
import {AppComponent} from './app.component';
import {ChatBoxComponent} from "./chat/chat-box.component";
import {ChatBoxDirective} from "./chat/chat-box.directive";
import {FooterComponent} from "./layout/footer.component";
import {HeaderComponent} from "./layout/header.component";
import {LoginComponent} from "./auth/login.component";
import {LogoutComponent} from "./auth/logout.component";
import {ProfileComponent} from "./auth/profile.component";
import {RecoverPasswordComponent} from "./auth/recover-password.component";
import {SearchBoxComponent} from "./search/searchBox.component";
import {SearchResultComponent} from "./search/search-result.component";
import {SignupComponent} from "./auth/signup.component";


// @providers - > services
import {AuthService} from "./auth/auth.service";
import {SetLocationService} from "./auth/set-location.service";
import {SearchService} from "./search/search.service";

@NgModule({
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule,
    routing
  ],
  declarations: [
    AccountComponent,
    AppComponent,
    ChatBoxComponent,
    ChatBoxDirective,
    FooterComponent,
    HeaderComponent,
    LoginComponent,
    LogoutComponent,
    ProfileComponent,
    RecoverPasswordComponent,
    SearchBoxComponent,
    SearchResultComponent,
    SignupComponent
  ],
  providers : [
    AuthService,
    SetLocationService,
    SearchService,
    {provide: LocationStrategy, useClass: HashLocationStrategy}
  ],
  bootstrap: [
    AppComponent,
    HeaderComponent,
    FooterComponent
  ]
})

export class AppModule {}

My first problem is if I do not add 1.HeaderComponent, 2.FooterComponent in bootstrap of app.module, none of them(1.HeaderComponent, 2.FooterComponent) get loaded when root route is active (localhost:3000), but the SearchBoxComponent. I am kind of confused, since I did not see adding multiple components in bootstrap this in the official document.

My second problem is almost same as the first one. If I embed a component (seachBoxConmponent) in another component like the following code, seachBoxConmponent component does not get loaded but the other parts.

@Component({
    selector: "search-result",
    template : `
            <seachBox></searchBox>
    <div class="tag_list">
      <p *ngFor = "let tag of result.obj.tags" class = "tag-li" >
        <a [routerLink] = "['/search', tag]" (click) = "onSearchCliked($event, tag)"> {{tag}} </a>
      </p>
    </div>
`
})

I was wondering , can anyone please help me, I have been working on this problem for last couple of days, still I am stuck here.

Alex Sartan Alex Sartan · Accepted Answer · 2016-08-21T05:45:06

Make sure the module that declares a component exports it. Otherwise this component will not be visible to other components trying to use it.

I would suggest creating separate modules for discrete concerns such as search, signup, chat, etc. and following the pattern below to share their components.

I've noticed that Angular2 fails silently when a component being used is not in scope. You'll add a component to the template and it'll just not render, no error. Before RC5 it usually meant you did not specify the desired component in the directives:[] array. With RC5, it probably means you're not exporting the component from the module that declares it and/or importing it in the module that wants to use it.

FooModule declares and exports FooComponent, exposing it for use by other components (potentially in other modules):

@NgModule({
    declarations: [FooComponent],
    imports: [BrowserModule, FormsModule],
    exports: [FooComponent]

})
export class FooModule {}

FooComponent:

@Component({
    selector: 'foo',
    template: `FOO`
})
export class FooComponent {}

BarModule imports FooModule, gaining access to the components it exposes (namely FooComponent):

@NgModule({
    declarations: [BarComponent],
    imports: [FooModule, FormsModule],
    exports: [BarComponent]

})
export class BarModule {}

BarComponent can access FooComponent and use it in the template:

@Component({
    selector: 'bar',
    template: `<foo></foo>BAR`
})
export class BarComponent {}

Angular2 rc5> component does not get loaded

3 Answers