简介
resolve保证了数据获取后再进行路由跳转，防止因为数据延迟而出现短暂的空组件情况，以此增强用户体验。
应用resolve还可以进行路由拦截，例如某些网站如果用户未登录，在跳转到某一页面时会提示未登录然后强行回跳至前一页面，这时如果使用resolve就可以在跳转发生前判断登录状态以决定是否允许跳转。
示例中跳转逻辑为 home.component => resolve.service => detail.component
import { NgModule } from '@angular/core'; import { RouterModule, Routes } from '@angular/router'; import { DetailResolver } from './detail-resolver.service'; import { DetailComponent } from './detail.component'; const routes: Routes = [ { path: ':id', component: DetailComponent, resolve: { // 此处使用resolve detail: DetailResolver } }, ]; @NgModule({ imports: [ RouterModule.forChild(routes) ], exports: [ RouterModule ], providers: [ DetailResolver ] }) export class HomeRoutingModule { }
import { Injectable } from '@angular/core'; import { Router, Resolve, RouterStateSnapshot, ActivatedRouteSnapshot } from '@angular/router'; import { Observable } from 'rxjs'; import { map, take } from 'rxjs/operators'; import { detail, DetailService } from './detail.service'; @Injectable() export class DetailResolver implements Resolve<Detail> { constructor(private detailService: DetailService, private router: Router) {} resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<Detail> { let id = route.paramMap.get('id'); return this.detailService.getDetail(id).pipe( take(1), // 可选，只发出源 Observable 最初发出的的1个值 map(res => { if (res) { return res; } else { // 请求失败时拦截跳转 this.router.navigate(['/home']); return null; } }) ); } }
由路由器提供的 Observable 必须完成，否则导航不会继续。
// 通过 route 获取 detail-resolver.service 中 detailService.getDetail 请求的数据 ngOnInit() { this.route.data .subscribe((data: { detail: Detail }) => { this.detail = data.detail; }); }
API地址 <resolve守卫>
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