Angular 2+ 中，懒加载 + 辅助路由 + 路由策略 三者结合时的报错赏析

Angular 2+ 中辅助路由的应用之前也已经写过了，大概如下：
代码中：

测试1

地址栏中：

http://localhost:4200/#/components/buttons(aux:pages/404)

路由设置：

import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';

// Import Containers
import {
FullLayoutComponent,
SimpleLayoutComponent
} from './containers';

export const routes: Routes = [
{
    path: 'components',
    loadChildren: './views/components/components.module#ComponentsModule'
},
{
    path: 'editors',
    loadChildren: './views/editors/editors.module#EditorsModule'
},
{
    path: 'pages',
    component: SimpleLayoutComponent,
    outlet: 'aux',
    data: {
    title: 'Pages'
    },
    children: [
    {
        path: '',
        loadChildren: './views/pages/pages.module#PagesModule',
    }
    ]
}
];

@NgModule({
imports: [ RouterModule.forRoot(routes) ],
exports: [ RouterModule ]
})
export class AppRoutingModule {}

界面：
In app.component.html

In app-aside.component.html

In simple-layout.component.ts

import { Component } from '@angular/core';
@Component({
  template: '',
})
export class SimpleLayoutComponent { }

In editors-routing.module.ts

import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';
const routes: Routes = [
  {
    path: '',
    data: {
      title: 'Editors'
    },
    children: [
      {
        path: 'text-editors',
        loadChildren: './text-editors/text-editors.module#TextEditorsModule'
      },
      {
        path: 'code-editors',
        loadChildren: './code-editors/code-editors.module#CodeEditorsModule'
      }
    ]
  }
];
@NgModule({
  imports: [RouterModule.forChild(routes)],
  exports: [RouterModule]
})
export class EditorsRoutingModule {}

之前的路由策略：

export class CustomReuseStrategy implements RouteReuseStrategy {
    handlers: {[key: string]: DetachedRouteHandle} = {};
    shouldDetach(route: ActivatedRouteSnapshot): boolean {
        console.debug('CustomReuseStrategy:shouldDetach', route);
        return true;
    }
    store(route: ActivatedRouteSnapshot, handle: DetachedRouteHandle): void {
        console.debug('CustomReuseStrategy:store', route, handle);
        this.handlers[route.routeConfig.path] = handle;
    }
    shouldAttach(route: ActivatedRouteSnapshot): boolean {
        console.debug('CustomReuseStrategy:shouldAttach', route);
        return !!route.routeConfig && !!this.handlers[route.routeConfig.path];
    }
    retrieve(route: ActivatedRouteSnapshot): DetachedRouteHandle {
        console.debug('CustomReuseStrategy:retrieve', route);
        return this.handlers[route.routeConfig.path];//从暂存处取回
    }
    shouldReuseRoute(future: ActivatedRouteSnapshot, curr: ActivatedRouteSnapshot): boolean {
        //在此处可以取得跳转前和跳转后的路由路径
        console.debug('CustomReuseStrategy:shouldReuseRoute', future, curr);
        return future.routeConfig === curr.routeConfig;
    }
}

加上路由策略以后就会使得带辅助路由的跳转报错：

Cannot reattach ActivatedRouteSnapshot created from a different route

这个问题之前在 Angular 的 Git 上的那个 issue： Cannot reattach ActivatedRouteSnapshot created from a different route 存在了一年多，并没有解决，包括查阅了网上的各种偏方，也并不好使，后来好不容易百度到这样的解决方案：

后来的路由策略：

import { RouteReuseStrategy, DefaultUrlSerializer, ActivatedRouteSnapshot, DetachedRouteHandle } from '@angular/router';

export class SimpleReuseStrategy implements RouteReuseStrategy {
  public static handlers: { [key: string]: DetachedRouteHandle } = {};
  /** 表示对所有路由允许复用 如果你有路由不想利用可以在这加一些业务逻辑判断 */
  public shouldDetach(route: ActivatedRouteSnapshot): boolean {
    return true;
  }
  /** 当路由离开时会触发。按path作为key存储路由快照&组件当前实例对象 */
  public store(route: ActivatedRouteSnapshot, handle: DetachedRouteHandle): void {
    SimpleReuseStrategy.handlers[route.routeConfig.path] = handle
  }
  /** 若 path 在缓存中有的都认为允许还原路由 */
  public shouldAttach(route: ActivatedRouteSnapshot): boolean {
    return !!route.routeConfig && !!SimpleReuseStrategy.handlers[route.routeConfig.path]
  }
  /** 从缓存中获取快照，若无则返回nul */
  public retrieve_bak(route: ActivatedRouteSnapshot): DetachedRouteHandle {
    if (!route.routeConfig) {
      return null
    }
    return SimpleReuseStrategy.handlers[route.routeConfig.path]
  }
  public retrieve(route: ActivatedRouteSnapshot): DetachedRouteHandle {
    if (!route.routeConfig) {
      return null;
    }
    if (route.routeConfig.loadChildren) {
      return null;
    }
    return SimpleReuseStrategy.handlers[route.routeConfig.path];
  }
  /** 进入路由触发，判断是否同一路由 */
  public shouldReuseRoute(future: ActivatedRouteSnapshot, curr: ActivatedRouteSnapshot): boolean {
    return future.routeConfig === curr.routeConfig
  }
}

实践证明这个并不会报错，是可以用的，Payload 就是这个函数：

retrieve(route: ActivatedRouteSnapshot): DetachedRouteHandle {
  if (!route.routeConfig) return null;
  if(route.routeConfig.loadChildren) return null;
  return this.handlers[route.routeConfig.path];
}

总之 Angular 的路由是极其重要的组件，也是存在问题比较多的组件。

参考资料：

• Error: Cannot reattach ActivatedRouteSnapshot created from a different route