Angular 2 rc5 component fails to load

After transitioning from Angular2 RC4 to RC5, I've been facing some issues. I can't tell if these problems are due to my errors or the transition itself. Here's how my app component looks:

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();
  }
}

Here's the 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);

Regarding the 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';

// @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 {}

One issue I'm facing is that if I don't include HeaderComponent and FooterComponent in the bootstrap of app.module, they don't load when the root route is active (localhost:3000), only the SearchBoxComponent does. I'm confused because I didn't see adding multiple components in bootstrap in the official documentation.

My second issue is similar to the first one. If I embed a component (SearchBoxComponent) into another component like the following code, the SearchBoxComponent doesn't load but the other parts do.

@Component({
    selector: "search-result",
    template : `
            <searchBox></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've been stuck on these problems for the past few days, so any help would be greatly appreciated. Thank you!

Answer №1

Ensure that components are properly exported from their modules to make them visible to other components that need to use them.

To avoid issues, it is recommended to create separate modules for different functionalities like search, signup, chat, etc. and follow a certain pattern to share their components effectively.

In my experience, Angular2 tends to fail silently when a component is not in scope. This means that if you add a component to the template and it doesn't render without any error, you might have forgotten to export it from the declaring module or import it in the module that requires it, especially with the changes in RC5.

For instance, the FooModule declares and exports the FooComponent to allow other components to use it:

@NgModule({
    declarations: [FooComponent],
    imports: [BrowserModule, FormsModule],
    exports: [FooComponent]
})
export class FooModule {}

And the BarModule imports the FooModule to access the components it exposes, such as the FooComponent:

@NgModule({
    declarations: [BarComponent],
    imports: [FooModule, FormsModule],
    exports: [BarComponent]
})
export class BarModule {}

In this setup, the BarComponent can utilize the FooComponent in its template:

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

Answer №2

Transitioning to RC5 has been a challenge for me as well. Remember, only AppComponent should be included in the bootstrap section. If a component is accessed through the router, it should not be listed in declarations. Instead, use export default class ComponentName for that component.

My strategy for tackling this migration is to comment out all existing code and gradually reintroduce components and services one by one.

Answer №3

Big thanks to everyone who pitched in to help me out. Finally, I managed to crack the code. It turns out that I had mistakenly included ROUTER_DIRECTIVES in both the HeaderComponent and FooterComponent, causing conflicts. The issue lies in the fact that "RouterModule" already provides ROUTER_DIRECTIVES implicitly, so there's no need to include it again in any component. By removing this directive, I was able to resolve the problem that had been plaguing me for nearly a week. I also had to update the outdated routerLike style in line with the current documentation.

Shoutout to Alex Sartan for breaking down the problem and offering a solution. I was able to address the issue without having to create separate modules for each concern, although it's generally recommended to keep concerns separated. Your input was invaluable. Thank you!

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