Angular 路由

1. 概述

在 Angular 中，路由是以模块为单位的，每个模块都可以有自己的路由

---

2. 快速上手

1. 创建页面组件、Layout 组件以及 Navigation 组件，供路由使用

   1. 创建首页页面组件

      ng g c pages/home
      

   2. 创建关于我们页面组件

      ng g c pages/about
      

   3. 创建布局组件

      ng g c pages/layout
      

   4. 创建导航组件

      ng g c pages/navigation
      

2. 创建路由规则

   // app.module.ts
   import { Routes } from "@angular/router"
   
   const routes: Routes = [
     {
       path: "home",
       component: HomeComponent
     },
     {
       path: "about",
       component: AboutComponent
     }
   ]
   

3. 引入路由模块并启动

   // app.module.ts
   import { RouterModule, Routes } from "@angular/router"
   
   @NgModule({
     imports: [RouterModule.forRoot(routes, { useHash: true })],
   })
   export class AppModule {}
   

4. 添加路由插座

   <!-- 路由插座即占位组件 匹配到的路由组件将会显示在这个地方 -->
   <router-outlet></router-outlet>
   

5. 在导航组件中定义链接

   <a routerLink="/home">首页</a>
   <a routerLink="/about">关于我们</a>
   

---

3. 匹配规则

3.1 重定向

const routes: Routes = [
  {
    path: "home",
    component: HomeComponent
  },
  {
    path: "about",
    component: AboutComponent
  },
  {
    path: "",
    // 重定向
    redirectTo: "home",
    // 完全匹配
    pathMatch: "full"
  }
]

3.2 404 页面

const routes: Routes = [
  {
    path: "home",
    component: HomeComponent
  },
  {
    path: "**",
    component: NotFoundComponent
  }
]

---

4. 路由传参

4.1 查询参数

<a routerLink="/about" [queryParams]="{ name: 'kitty' }">关于我们</a>

import { ActivatedRoute } from "@angular/router"

export class AboutComponent implements OnInit {
  constructor(private route: ActivatedRoute) {}

  ngOnInit(): void {
    this.route.queryParamMap.subscribe(query => {
      query.get("name")
    })
  }
}

4.2 动态参数

const routes: Routes = [
  {
    path: "home",
    component: HomeComponent
  },
  {
    path: "about/:name",
    component: AboutComponent
  }
]

<a [routerLink]="['/about', 'zhangsan']">关于我们</a>

import { ActivatedRoute } from "@angular/router"

export class AboutComponent implements OnInit {
  constructor(private route: ActivatedRoute) {}

  ngOnInit(): void {
    this.route.paramMap.subscribe(params => {
      params.get("name")
    })
  }
}

---

5. 路由嵌套

路由嵌套指的是如何定义子级路由

const routes: Routes = [
  {
    path: "about",
    component: AboutComponent,
    children: [
      {
        path: "introduce",
        component: IntroduceComponent
      },
      {
        path: "history",
        component: HistoryComponent
      }
    ]
  }
]

<!-- about.component.html -->
<app-layout>
  <p>about works!</p>
  <a routerLink="/about/introduce">公司简介</a>
  <a routerLink="/about/history">发展历史</a>
  <div>
    <router-outlet></router-outlet>
  </div>
</app-layout>

---

6. 命名插座

将子级路由组件显示到不同的路由插座中

{
  path: "about",
  component: AboutComponent,
  children: [
    {
      path: "introduce",
      component: IntroduceComponent,
      outlet: "left"
    },
    {
      path: "history",
      component: HistoryComponent,
      outlet: "right"
    }
  ]
}

<!-- about.component.html -->
<app-layout>
  <p>about works!</p>
  <router-outlet name="left"></router-outlet>
  <router-outlet name="right"></router-outlet>
</app-layout>

<a
    [routerLink]="[
      '/about',
      {
        outlets: {
          left: ['introduce'],
          right: ['history']
        }
      }
    ]"
>关于我们</a>

---

7. 导航路由

<!-- app.component.html -->
<button (click)="jump()">跳转到发展历史</button>

// app.component.ts
import { Router } from "@angular/router"

export class HomeComponent {
  constructor(private router: Router) {}
  jump() {
    this.router.navigate(["/about/history"], {
      queryParams: {
        name: "Kitty"
      }
    })
  }
}

---

8. 路由模块

将根模块中的路由配置抽象成一个单独的路由模块，称之为根路由模块，然后在根模块中引入根路由模块

import { NgModule } from "@angular/core"

import { HomeComponent } from "./pages/home/home.component"
import { NotFoundComponent } from "./pages/not-found/not-found.component"

const routes: Routes = [
  {
    path: "",
    component: HomeComponent
  },
  {
    path: "**",
    component: NotFoundComponent
  }
]

@NgModule({
  declarations: [],
  imports: [RouterModule.forRoot(routes, { useHash: true })],
  // 导出 Angular 路由功能模块，因为在根模块的根组件中使用了 RouterModule 模块中提供的路由插座组件
  exports: [RouterModule]
})
export class AppRoutingModule {}

import { BrowserModule } from "@angular/platform-browser"
import { NgModule } from "@angular/core"
import { AppComponent } from "./app.component"
import { AppRoutingModule } from "./app-routing.module"

@NgModule({
  declarations: [AppComponent],
  imports: [BrowserModule, AppRoutingModule],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule {}

---

9. 路由懒加载

路由懒加载是以模块为单位的

1. 创建用户模块 ng g m user --routing=true 并创建该模块的路由模块

2. 创建登录页面组件 ng g c user/pages/login

3. 创建注册页面组件 ng g c user/pages/register

4. 配置用户模块的路由规则

import { NgModule } from "@angular/core"
import { Routes, RouterModule } from "@angular/router"
import { LoginComponent } from "./pages/login/login.component"
import { RegisterComponent } from "./pages/register/register.component"

const routes: Routes = [
  {
    path: "login",
    component: LoginComponent
  },
  {
    path: "register",
    component: RegisterComponent
  }
]

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

1. 将用户路由模块关联到主路由模块

   // app-routing.module.ts
   const routes: Routes = [
     {
       path: "user",
       loadChildren: () => import("./user/user.module").then(m => m.UserModule)
     }
   ]
   

2. 在导航组件中添加访问链接

   <a routerLink="/user/login">登录</a>
   <a routerLink="/user/register">注册</a>
   

---

10. 路由守卫

路由守卫会告诉路由是否允许导航到请求的路由

路由守方法可以返回 boolean 或 Observable \<boolean\> 或 Promise \<boolean\>，它们在将来的某个时间点解析为布尔值

10.1 CanActivate

检查用户是否可以访问某一个路由

CanActivate 为接口，路由守卫类要实现该接口，该接口规定类中需要有 canActivate 方法，方法决定是否允许访问目标路由

路由可以应用多个守卫，所有守卫方法都允许，路由才被允许访问，有一个守卫方法不允许，则路由不允许被访问

创建路由守卫：ng g guard guards/auth

import { Injectable } from "@angular/core"
import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot, UrlTree, Router } from "@angular/router"
import { Observable } from "rxjs"

@Injectable({
  providedIn: "root"
})
export class AuthGuard implements CanActivate {
  constructor(private router: Router) {}
  canActivate(): boolean | UrlTree {
    // 用于实现跳转
    return this.router.createUrlTree(["/user/login"])
    // 禁止访问目标路由
    return false
    // 允许访问目标路由
    return true
  }
}

{
  path: "about",
  component: AboutComponent,
  canActivate: [AuthGuard]
}

10.2 CanActivateChild

检查用户是否方可访问某个子路由

创建路由守卫：ng g guard guards/admin

注意：选择 CanActivateChild，需要将箭头移动到这个选项并且敲击空格确认选择

import { Injectable } from "@angular/core"
import { CanActivateChild, ActivatedRouteSnapshot, RouterStateSnapshot, UrlTree } from "@angular/router"
import { Observable } from "rxjs"

@Injectable({
  providedIn: "root"
})
export class AdminGuard implements CanActivateChild {
  canActivateChild(): boolean | UrlTree {
    return true
  }
}

{
  path: "about",
  component: AboutComponent,
  canActivateChild: [AdminGuard],
  children: [
    {
      path: "introduce",
      component: IntroduceComponent
    }
  ]
}

10.3 CanDeactivate

检查用户是否可以退出路由。比如用户在表单中输入的内容没有保存，用户又要离开路由，此时可以调用该守卫提示用户

import { Injectable } from "@angular/core"
import {
  CanDeactivate,
  ActivatedRouteSnapshot,
  RouterStateSnapshot,
  UrlTree
} from "@angular/router"
import { Observable } from "rxjs"

export interface CanComponentLeave {
  canLeave: () => boolean
}

@Injectable({
  providedIn: "root"
})
export class UnsaveGuard implements CanDeactivate<CanComponentLeave> {
  canDeactivate(component: CanComponentLeave): boolean {
    if (component.canLeave()) {
      return true
    }
    return false
  }
}

{
  path: "",
  component: HomeComponent,
  canDeactivate: [UnsaveGuard]
}

import { CanComponentLeave } from "src/app/guards/unsave.guard"

export class HomeComponent implements CanComponentLeave {
  myForm: FormGroup = new FormGroup({
    username: new FormControl()
  })
  canLeave(): boolean {
    if (this.myForm.dirty) {
      if (window.confirm("有数据未保存, 确定要离开吗")) {
        return true
      } else {
        return false
      }
    }
    return true
  }

10.4 Resolve

允许在进入路由之前先获取数据，待数据获取完成之后再进入路由

ng g resolver <name>

import { Injectable } from "@angular/core"
import { Resolve } from "@angular/router"

type returnType = Promise<{ name: string }>

@Injectable({
  providedIn: "root"
})
export class ResolveGuard implements Resolve<returnType> {
  resolve(): returnType {
    return new Promise(function (resolve) {
      setTimeout(() => {
        resolve({ name: "张三" })
      }, 2000)
    })
  }
}

{
   path: "",
   component: HomeComponent,
   resolve: {
     user: ResolveGuard
   }
}

export class HomeComponent {
  constructor(private route: ActivatedRoute) {}
  ngOnInit(): void {
    console.log(this.route.snapshot.data.user)
  }
}