docs(router): Added example of feature module pre-loading (#2595)
* added example of feature module pre-loading * added transition aliases for route animations
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@ -27,7 +27,10 @@ describe('Router', function () {
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heroDetailTitle: element(by.css('my-app > ng-component > div > h3')),
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adminHref: hrefEles.get(2),
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loginHref: hrefEles.get(3)
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adminPreloadList: element.all(by.css('my-app > ng-component > ng-component > ul > li')),
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loginHref: hrefEles.get(3),
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loginButton: element.all(by.css('my-app > ng-component > p > button')),
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};
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}
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@ -105,6 +108,16 @@ describe('Router', function () {
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});
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});
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it('should be able to see the preloaded modules', function () {
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let page = getPageStruct();
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page.loginHref.click().then(function() {
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return page.loginButton.click();
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}).then(function() {
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expect(page.adminPreloadList.count()).toBe(1, 'should be 1 preloaded module');
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expect(page.adminPreloadList.first().getText()).toBe('crisis-center', 'first preload should be crisis center');
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});
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});
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function crisisCenterEdit(index: number, shouldSave: boolean) {
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let page = getPageStruct();
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let crisisEle: ElementFinder;
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@ -0,0 +1,33 @@
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// #docregion
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import { Component, OnInit } from '@angular/core';
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import { ActivatedRoute } from '@angular/router';
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import { Observable } from 'rxjs/Observable';
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import 'rxjs/add/operator/map';
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@Component({
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template: `
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<p>Dashboard</p>
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<p>Session ID: {{ sessionId | async }}</p>
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<a id="anchor"></a>
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<p>Token: {{ token | async }}</p>
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`
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})
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export class AdminDashboardComponent implements OnInit {
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sessionId: Observable<string>;
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token: Observable<string>;
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constructor(private route: ActivatedRoute) {}
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ngOnInit() {
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// Capture the session ID if available
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this.sessionId = this.route
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.queryParams
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.map(params => params['session_id'] || 'None');
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// Capture the fragment if available
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this.token = this.route
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.fragment
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.map(fragment => fragment || 'None');
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}
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}
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@ -1,7 +1,9 @@
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// #docregion
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import { Component, OnInit } from '@angular/core';
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import { ActivatedRoute } from '@angular/router';
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import { Observable } from 'rxjs/Observable';
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import { Component, OnInit } from '@angular/core';
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import { ActivatedRoute } from '@angular/router';
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import { Observable } from 'rxjs/Observable';
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import { PreloadSelectedModules } from '../selective-preload-strategy';
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import 'rxjs/add/operator/map';
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@Component({
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@ -11,13 +13,24 @@ import 'rxjs/add/operator/map';
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<p>Session ID: {{ sessionId | async }}</p>
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<a id="anchor"></a>
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<p>Token: {{ token | async }}</p>
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Preloaded Modules
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<ul>
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<li *ngFor="let module of modules">{{ module }}</li>
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</ul>
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`
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})
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export class AdminDashboardComponent implements OnInit {
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sessionId: Observable<string>;
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token: Observable<string>;
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modules: string[];
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constructor(private route: ActivatedRoute) {}
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constructor(
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private route: ActivatedRoute,
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private preloadStrategy: PreloadSelectedModules
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) {
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this.modules = preloadStrategy.preloadedModules;
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}
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ngOnInit() {
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// Capture the session ID if available
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@ -0,0 +1,33 @@
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// #docplaster
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// #docregion
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import { NgModule } from '@angular/core';
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// #docregion import-router
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import { RouterModule } from '@angular/router';
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// #enddocregion import-router
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import { CanDeactivateGuard } from './can-deactivate-guard.service';
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// #docregion can-load-guard
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import { AuthGuard } from './auth-guard.service';
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// #enddocregion can-load-guard
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// #docregion lazy-load-admin, can-load-guard
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@NgModule({
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imports: [
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RouterModule.forRoot([
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{
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path: 'admin',
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loadChildren: 'app/admin/admin.module#AdminModule',
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// #enddocregion lazy-load-admin
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canLoad: [AuthGuard]
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// #docregion lazy-load-admin
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}
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])
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],
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exports: [
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RouterModule
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],
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providers: [
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CanDeactivateGuard
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]
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})
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export class AppRoutingModule {}
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@ -0,0 +1,44 @@
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// #docplaster
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// #docregion, preload-v1
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import { NgModule } from '@angular/core';
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import {
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RouterModule,
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// #enddocregion preload-v1
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PreloadAllModules
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// #docregion preload-v1
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} from '@angular/router';
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import { CanDeactivateGuard } from './can-deactivate-guard.service';
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import { AuthGuard } from './auth-guard.service';
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@NgModule({
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imports: [
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RouterModule.forRoot([
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{
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path: 'admin',
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loadChildren: 'app/admin/admin.module#AdminModule',
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canLoad: [AuthGuard]
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},
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{
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path: '',
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redirectTo: '/heroes',
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pathMatch: 'full'
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},
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{
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path: 'crisis-center',
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loadChildren: 'app/crisis-center/crisis-center.module#CrisisCenterModule'
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},
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],
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// #enddocregion preload-v1
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{ preloadingStrategy: PreloadAllModules }
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// #docregion preload-v1
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)
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],
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exports: [
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RouterModule
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],
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providers: [
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CanDeactivateGuard
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]
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})
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export class AppRoutingModule {}
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@ -1,33 +1,43 @@
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// #docplaster
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// #docregion
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// #docregion, preload-v1
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import { NgModule } from '@angular/core';
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// #docregion import-router
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import { RouterModule } from '@angular/router';
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// #enddocregion import-router
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import { CanDeactivateGuard } from './can-deactivate-guard.service';
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// #docregion can-load-guard
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import { AuthGuard } from './auth-guard.service';
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// #enddocregion can-load-guard
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import { PreloadSelectedModules } from './selective-preload-strategy';
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// #docregion lazy-load-admin, can-load-guard
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@NgModule({
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imports: [
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RouterModule.forRoot([
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{
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path: 'admin',
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loadChildren: 'app/admin/admin.module#AdminModule',
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// #enddocregion lazy-load-admin
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canLoad: [AuthGuard]
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// #docregion lazy-load-admin
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},
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{
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path: '',
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redirectTo: '/heroes',
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pathMatch: 'full'
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},
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// #docregion preload-v2
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{
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path: 'crisis-center',
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loadChildren: 'app/crisis-center/crisis-center.module#CrisisCenterModule',
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data: {
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preload: true
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}
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}
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])
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// #enddocregion preload-v2
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],
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{ preloadingStrategy: PreloadSelectedModules })
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],
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exports: [
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RouterModule
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],
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providers: [
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CanDeactivateGuard
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CanDeactivateGuard,
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PreloadSelectedModules
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]
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})
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export class AppRoutingModule {}
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@ -9,6 +9,8 @@ import { AppRoutingModule } from './app-routing.module';
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import { HeroesModule } from './heroes/heroes.module';
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import { CrisisCenterModule } from './crisis-center/crisis-center.module';
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import { LoginRoutingModule } from './login-routing.module';
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import { LoginComponent } from './login.component';
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import { DialogService } from './dialog.service';
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@NgModule({
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AppRoutingModule
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],
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declarations: [
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AppComponent
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AppComponent,
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LoginComponent
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],
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providers: [
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DialogService
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@ -5,11 +5,9 @@ import { FormsModule } from '@angular/forms';
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import { AppComponent } from './app.component';
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import { AppRoutingModule } from './app-routing.module';
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import { LoginRoutingModule } from './login-routing.module';
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import { HeroesModule } from './heroes/heroes.module';
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import { CrisisCenterModule } from './crisis-center/crisis-center.module';
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import { LoginRoutingModule } from './login-routing.module';
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import { LoginComponent } from './login.component';
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import { DialogService } from './dialog.service';
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@ -19,7 +17,6 @@ import { DialogService } from './dialog.service';
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BrowserModule,
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FormsModule,
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HeroesModule,
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CrisisCenterModule,
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LoginRoutingModule,
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AppRoutingModule
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],
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@ -0,0 +1,60 @@
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// #docplaster
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// #docregion
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import { NgModule } from '@angular/core';
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import { RouterModule } from '@angular/router';
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import { CrisisCenterHomeComponent } from './crisis-center-home.component';
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import { CrisisListComponent } from './crisis-list.component';
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import { CrisisCenterComponent } from './crisis-center.component';
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import { CrisisDetailComponent } from './crisis-detail.component';
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import { CanDeactivateGuard } from '../can-deactivate-guard.service';
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// #docregion crisis-detail-resolve
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import { CrisisDetailResolve } from './crisis-detail-resolve.service';
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@NgModule({
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imports: [
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RouterModule.forChild([
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// #docregion redirect
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{
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path: '',
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redirectTo: '/crisis-center',
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pathMatch: 'full'
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},
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// #enddocregion redirect
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{
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path: 'crisis-center',
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component: CrisisCenterComponent,
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children: [
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{
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path: '',
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component: CrisisListComponent,
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children: [
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{
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path: ':id',
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component: CrisisDetailComponent,
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canDeactivate: [CanDeactivateGuard],
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resolve: {
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crisis: CrisisDetailResolve
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}
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},
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{
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path: '',
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component: CrisisCenterHomeComponent
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}
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]
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}
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]
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}
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])
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],
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exports: [
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RouterModule
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],
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providers: [
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CrisisDetailResolve
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]
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})
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export class CrisisCenterRoutingModule { }
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// #enddocregion
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@ -16,15 +16,8 @@ import { CrisisDetailResolve } from './crisis-detail-resolve.service';
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@NgModule({
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imports: [
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RouterModule.forChild([
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// #docregion redirect
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{
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path: '',
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redirectTo: '/crisis-center',
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pathMatch: 'full'
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},
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// #enddocregion redirect
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{
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path: 'crisis-center',
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component: CrisisCenterComponent,
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children: [
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{
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@ -35,14 +35,14 @@ import { DialogService } from '../dialog.service';
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transform: 'translateX(0)'
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})
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),
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transition('void => *', [
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transition(':enter', [
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style({
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opacity: 0,
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transform: 'translateX(-100%)'
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}),
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animate('0.2s ease-in')
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]),
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transition('* => void', [
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transition(':leave', [
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animate('0.5s ease-out', style({
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opacity: 0,
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transform: 'translateY(100%)'
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@ -34,14 +34,14 @@ import { DialogService } from '../dialog.service';
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transform: 'translateX(0)'
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})
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),
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transition('void => *', [
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transition(':enter', [
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style({
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opacity: 0,
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transform: 'translateX(-100%)'
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}),
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animate('0.2s ease-in')
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]),
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transition('* => void', [
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transition(':leave', [
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animate('0.5s ease-out', style({
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opacity: 0,
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transform: 'translateY(100%)'
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@ -34,14 +34,14 @@ import { Hero, HeroService } from './hero.service';
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transform: 'translateX(0)'
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})
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),
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transition('void => *', [
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transition(':enter', [
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style({
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opacity: 0,
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transform: 'translateX(-100%)'
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}),
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animate('0.2s ease-in')
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]),
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transition('* => void', [
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transition(':leave', [
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animate('0.5s ease-out', style({
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opacity: 0,
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transform: 'translateY(100%)'
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@ -0,0 +1,24 @@
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// #docregion
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import 'rxjs/add/observable/of';
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import { Injectable } from '@angular/core';
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import { PreloadingStrategy, Route } from '@angular/router';
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import { Observable } from 'rxjs/Observable';
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@Injectable()
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export class PreloadSelectedModules implements PreloadingStrategy {
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preloadedModules: string[] = [];
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preload(route: Route, load: Function): Observable<any> {
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if (route.data && route.data['preload']) {
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// add the route path to our preloaded module array
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this.preloadedModules.push(route.path);
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// log the route path to the console
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console.log('Preloaded: ' + route.path);
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return load();
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} else {
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return Observable.of(null);
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}
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}
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}
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@ -3,7 +3,7 @@
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"files":[
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"!**/*.d.ts",
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"!**/*.js",
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"!**/*.[1,2,3,4,5,6].*",
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"!**/*.[0-9].*",
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"!app/crisis-list.component.ts",
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"!app/hero-list.component.ts",
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"!app/crisis-center/add-crisis.component.ts",
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@ -59,6 +59,8 @@ include ../_util-fns
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* providing optional information across routes with [query parameters](#query-parameters)
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* jumping to anchor elements using a [fragment](#fragment)
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* loading feature areas [asynchronously](#asynchronous-routing)
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* pre-loading feature areas [during navigation](#preloading)
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* using a [custom strategy](#custom-preloading) to only pre-load certain features
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* choosing the "HTML5" or "hash" [URL style](#browser-url-styles)
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We proceed in phases marked by milestones building from a simple two-pager with placeholder views
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@ -1140,8 +1142,8 @@ h3#route-animation Adding animations to the route component
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:marked
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Next, we'll use a **host binding** for route animations named *@routeAnimation*. There is nothing special
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about the choice of the binding name, but since we are controlling route animation, we'll go with `routeAnimation`.
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The binding value is set to `true` because we only care about the `*` and `void` states which are
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[entering and leaving](../guide/animations.html#example-entering-and-leaving) animation states.
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The binding value is set to `true` because we only care about the `:enter` and `:leave` states which are
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[entering and leaving](../api/core/index/transition-function.html#transition-aliases-enter-and-leave-) transition aliases.
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We'll also add some display and positioning bindings for styling.
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@ -1150,8 +1152,8 @@ h3#route-animation Adding animations to the route component
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:marked
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Now we can build our animation trigger, which we'll call *routeAnimation* to match the binding we previously
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setup. We'll use the **wildcard state** that matches any animation state our route component is in, along with
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two *transitions*. One transition animates the component as it enters the application view (`void => *`), while the other
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animates the component as it leaves the application view (`* => void`).
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two *transitions*. One transition animates the component as it enters the application view (`:enter`), while the other
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animates the component as it leaves the application view (`:leave`).
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We could add different transitions to different route components depending on our needs. We'll just animate our `HeroDetailComponent` for this milestone.
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@ -1903,7 +1905,7 @@ h3#resolve-guard <i>Resolve</i>: pre-fetching component data
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We need the `Resolve` guard.
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### Preload route information
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### Fetch data before navigating
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We'll update our `Crisis Detail` route to resolve our Crisis before loading the route, or if the user happens to
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navigate to an invalid crisis center `:id`, we'll navigate back to our list of existing crises.
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@ -1935,7 +1937,7 @@ h3#resolve-guard <i>Resolve</i>: pre-fetching component data
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We'll add the `CrisisDetailResolve` service to our `CrisisCenterRoutingModule`'s `providers`, so its available to the `Router` during the navigation process.
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+makeExcerpt('app/crisis-center/crisis-center-routing.module.ts (resolve)', 'crisis-detail-resolve')
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+makeExcerpt('app/crisis-center/crisis-center-routing.module.4.ts (resolve)', 'crisis-detail-resolve')
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|
||||
:marked
|
||||
Now that we've added our `Resolve` guard to fetch data before the route loads, we no longer need to do this once we get into our `CrisisDetailComponent`.
|
||||
|
@ -1959,7 +1961,7 @@ h3#resolve-guard <i>Resolve</i>: pre-fetching component data
|
|||
`router/ts/app/app.component.ts,
|
||||
router/ts/app/crisis-center/crisis-center-home.component.ts,
|
||||
router/ts/app/crisis-center/crisis-center.component.ts,
|
||||
router/ts/app/crisis-center/crisis-center-routing.module.ts,
|
||||
router/ts/app/crisis-center/crisis-center-routing.module.4.ts,
|
||||
router/ts/app/crisis-center/crisis-list.component.ts,
|
||||
router/ts/app/crisis-center/crisis-detail.component.ts,
|
||||
router/ts/app/crisis-center/crisis-detail-resolve.service.ts,
|
||||
|
@ -2017,7 +2019,7 @@ a#fragment
|
|||
Since we'll be navigating to our *Admin Dashboard* route after logging in, we'll update it to handle our
|
||||
query parameters and fragment.
|
||||
|
||||
+makeExcerpt('app/admin/admin-dashboard.component.ts (v2)', '')
|
||||
+makeExcerpt('app/admin/admin-dashboard.component.2.ts (v2)', '')
|
||||
|
||||
:marked
|
||||
*Query Parameters* and *Fragments* are also available through the `ActivatedRoute` service available to route components.
|
||||
|
@ -2075,7 +2077,7 @@ a#fragment
|
|||
our child routes.
|
||||
|
||||
+makeTabs(
|
||||
`router/ts/app/app-routing.module.ts,
|
||||
`router/ts/app/app-routing.module.5.ts,
|
||||
router/ts/app/admin/admin-routing.module.ts`,
|
||||
'lazy-load-admin,',
|
||||
`app-routing.module.ts (load children),
|
||||
|
@ -2107,7 +2109,7 @@ a#fragment
|
|||
to break our `AdminModule` into a completely separate module. In our `app.module.ts`, we'll remove our `AdminModule` from the
|
||||
`imports` array since we'll be loading it on-demand an we'll remove the imported `AdminModule`.
|
||||
|
||||
+makeExcerpt('app/app.module.ts (async admin module)', '')
|
||||
+makeExcerpt('app/app.module.7.ts (async admin module)', '')
|
||||
|
||||
h3#can-load-guard <i>CanLoad Guard</i>: guarding against loading of feature modules
|
||||
:marked
|
||||
|
@ -2133,7 +2135,111 @@ h3#can-load-guard <i>CanLoad Guard</i>: guarding against loading of feature modu
|
|||
Next, we'll import the `AuthGuard` into our `app-routing.module.ts` and add the `AuthGuard` to the `canLoad` array for
|
||||
our `admin` route. Now our `admin` feature area is only loaded when the proper access has been granted.
|
||||
|
||||
+makeExcerpt('app/app-routing.module.ts (can load guard)', 'can-load-guard')
|
||||
+makeExcerpt('app/app-routing.module.5.ts (can load guard)', 'can-load-guard')
|
||||
|
||||
h3#preloading <i>Pre-Loading</i>: background loading of feature areas
|
||||
:marked
|
||||
We've learned how to load modules on-demand, but we can also take advantage of loading feature areas modules in *advance*. The *Router*
|
||||
supports **pre-loading** of asynchronous feature areas prior to navigation to their respective URL. Pre-loading allows us to to load our initial route
|
||||
quickly, while other feature modules are loaded in the background. Once we navigate to those areas, they will have already been loaded
|
||||
as if our they were included in our initial bundle.
|
||||
|
||||
Each time a **successful** navigation happens, the *Router* will look through our configuration for lazy loaded feature areas
|
||||
and react based on the provided strategy.
|
||||
|
||||
The *Router* supports two pre-loading strategies by default:
|
||||
|
||||
* No pre-loading at all which is the default. Lazy loaded feature areas are still loaded on demand.
|
||||
* Pre-loading of all lazy loaded feature areas.
|
||||
|
||||
The *Router* also supports [custom preloading strategies](#custom-preloading) to give us control of what we want to pre-load.
|
||||
|
||||
We'll update our *CrisisCenterModule* to be loaded lazily by default and use the `PreloadAllModules` strategy to eagerly
|
||||
it them up initial navigation.
|
||||
|
||||
<a id="preload-canload"></a>
|
||||
.l-sub-section
|
||||
:marked
|
||||
The **PreloadAllModules** strategy does not eagerly load feature areas protected by the [Can Load](#can-load-guard) and this is by design.
|
||||
The *CanLoad* guard protects against loading feature area assets until authorized to do so. If you want to eagerly load all modules and guard
|
||||
them against unauthorized access, use the [CanActivate](#can-activate-guard) guard instead.
|
||||
|
||||
:marked
|
||||
We'll update our route configuration to eagerly load the *CrisisCenterModule*. We follow the same process as we did when we loaded the *AdminModule* asynchronously.
|
||||
In the *crisis-center-routing.module.ts*, we'll change the *crisis-center* path to an *empty path* route.
|
||||
|
||||
We'll move our redirect and *crisis-center* route to our `AppRoutingModule` routes and use the `loadChildren` string to load the *CrisisCenterModule*.
|
||||
The redirect is also changed to load the `/heroes` route on initial load.
|
||||
|
||||
Once we're finished, we'll remove the `CrisisCenterModule` from our `AppModule`'s imports.
|
||||
|
||||
Here are our updated modules:
|
||||
|
||||
+makeTabs(
|
||||
`router/ts/app/app.module.ts,
|
||||
router/ts/app/app-routing.module.6.ts,
|
||||
router/ts/app/crisis-center/crisis-center-routing.module.ts
|
||||
`,
|
||||
',preload-v1,',
|
||||
`app.module.ts,
|
||||
app-routing.module.ts,
|
||||
crisis-center-routing.module.ts
|
||||
`)
|
||||
|
||||
:marked
|
||||
In order to enable pre-loading of all modules, we'll import the `PreloadAllModules` token from the router package. The second argument in the
|
||||
`RouterModule.forRoot` method takes an object where we can provide additional configuration options. We'll use the `preloadingStrategy` property
|
||||
with the `PreloadAllModules` token. This enables the built-in *Router* pre-loader to eagerly load **all** [unguarded](#preload-canload) feature areas that use `loadChildren`.
|
||||
|
||||
+makeExcerpt('app/app-routing.module.6.ts (preload all)', '')
|
||||
|
||||
:marked
|
||||
Now when we visit `http://localhost:3000`, the `/heroes` route will load in the foreground, while the *CrisisCenterModule* and any other asynchronous feature
|
||||
modules we could have are _eagerly_ loaded in the background, waiting for us to navigate to them.
|
||||
|
||||
<a id="custom-preloading"></a>
|
||||
:marked
|
||||
### Custom Pre-Loading Strategy
|
||||
|
||||
Pre-loading all modules works well in some situations, but in some cases we need more control over what gets loaded eagerly. This becomes more clear
|
||||
as we load our application on a mobile device, or a low bandwidth connection. We may only want to preload certain feature modules based on user metrics
|
||||
or other data points we gather over time. The *Router* lets us have more control with a **custom** preloading strategy.
|
||||
|
||||
We can define our own strategy the same way the **PreloadAllModules** modules strategy was provided to our *RouterModule.forRoot* configuration object.
|
||||
|
||||
Since we want to take advantage of this, we'll add a custom strategy that _only_ preloads the modules we select. We'll enable the preloading by using the *Route Data*,
|
||||
which we learned is an object to store arbitrary route data and and [resolve data](#resolve-guard).
|
||||
|
||||
We'll add a custom `preload` boolean to our `crisis-center` route data that we'll use with our custom strategy. To see it in action, we'll add to
|
||||
the `route.path` to the `preloadedModules` array in our custom strategy service. We'll also log a message
|
||||
to the console for the preloaded module.
|
||||
|
||||
+makeExcerpt('app/app-routing.module.ts (route data preload)', 'preload-v2')
|
||||
|
||||
:marked
|
||||
To create our custom strategy we'll need to implement the abstract `PreloadingStrategy` class and the `preload` method. The `preload` method is called for each route
|
||||
that loads its feature module asynchronously and determines whether to preload it. The `preload` method takes two arguments, the first being the `Route` that provides
|
||||
the route configuration and a function that preloads the feature module.
|
||||
|
||||
We'll name our strategy **PreloadSelectedModules** since we _only_ want to preload based on certain criteria. Our custom strategy looks for the **`preload`** boolean
|
||||
value in our `Route Data` and if its true, it calls the `load` function provided by the built-in `Router` pre-loader that eagerly loads feature modules.
|
||||
|
||||
+makeExcerpt('app/selective-preload-strategy.ts (preload selected modules)', '')
|
||||
|
||||
:marked
|
||||
In order to use our custom preloading strategy, we import it into our `app-routing.module.ts` and replace the `PreloadAllModules` strategy. We also add
|
||||
the `PreloadSelectedModules` strategy to the `AppRoutingModule` providers array. This allows the *Router* pre-loader to inject our custom strategy.
|
||||
|
||||
To confirm our *CrisisCenterModule* is being pre-loaded, we'll display our `preloadedModules` in the `Admin` dashboard. We already know how to use
|
||||
an *ngFor* loop, so we'll skip over the details here. Since the `PreloadSelectedModules` is just a service, we can inject it into the `AdminDashboardComponent`
|
||||
and wire it up to our list.
|
||||
|
||||
+makeExcerpt('app/admin/admin-dashboard.component.ts (preloaded modules)', '')
|
||||
|
||||
:marked
|
||||
Once our application is loaded to our initial route, the *CrisisCenterModule* is loaded eagerly. We can verify this by logging in to the `Admin` feature area and
|
||||
noting that the `crisis-center` is listed in the `Preloaded Modules` and logged to the console. We can continue to add feature modules to be selectively loaded eagerly.
|
||||
|
||||
|
||||
<a id="final-app"></a>
|
||||
.l-main-section
|
||||
|
|
Loading…
Reference in New Issue