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深入瞭解Angular中的路由，如何快速上手？

2021-09-24 13:00:40
本篇文章帶大家深入瞭解一下中的路由，看看快速上手的方法，介紹一下匹配規則、路由傳參、路由巢狀、路由守衛等，希望對大家有所幫助！

在 Angular 中，路由是以模組為單位的，每個模組都可以有自己的路由。【相關教學推薦：《》】

快速上手

建立頁面元件、Layout 元件以及 Navigation 元件，供路由使用

  • 建立首頁頁面元件ng g c pages/home

  • 建立關於我們頁面元件ng g c pages/about

  • 建立佈局元件ng g c pages/layout

  • 建立導航元件ng g c pages/navigation

建立路由規則

// app.module.ts
import { Routes } from "@angular/router"

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

引入路由模組並啟動

// app.module.ts
import { RouterModule, Routes } from "@angular/router"

@NgModule({
  imports: [RouterModule.forRoot(routes, { useHash: true })],
})
export class AppModule {}

新增路由插座

<!-- 路由插座即佔位元件 匹配到的路由元件將會顯示在這個地方 -->
<router-outlet></router-outlet>

在導航元件中定義連結

<a routerLink="/home">首頁</a>
<a routerLink="/about">關於我們</a>

匹配規則

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"
  }
]

2、404 頁面

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

路由傳參

1、查詢引數

<a routerLink="/about" [queryParams]="{ name: 'kitty' }">關於我們</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")
    })
  }
}

2、動態引數

const routes: Routes = [
  {
    path: "home",
    component: HomeComponent
  },
  {
    path: "about/:name",
    component: AboutComponent
  }
]
<a [routerLink]="['/about', 'zhangsan']">關於我們</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")
    })
  }
}

路由巢狀

路由巢狀指的是如何定義子級路由

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">公司簡介</a>
  <a routerLink="/about/history">發展歷史</a>
  <div>
    <router-outlet></router-outlet>
  </div>
</app-layout>

命名插座

將子級路由元件顯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']
        }
      }
    ]"
>關於我們</a>

導航路由

<!-- app.component.html -->
<button (click)="jump()">跳轉到發展歷史</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"
      }
    })
  }
}

路由模組

將根模組中的路由設定抽象成一個單獨的路由模組，稱之為根路由模組，然後在根模組中引入根路由模組

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 })],
  // 匯出 Angular 路由功能模組，因為在根模組的根元件中使用了 RouterModule 模組中提供的路由插座元件
  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 {}

路由懶載入

路由懶載入是以模組為單位的。

  • 建立使用者模組 ng g m user --routing=true 並建立該模組的路由模組

  • 建立登入頁面元件 ng g c user/pages/login

  • 建立註冊頁面元件 ng g c user/pages/register

  • 設定使用者模組的路由規則

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 {}

  • 將使用者路由模組關聯到主路由模組

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

  • 在導航元件中新增存取連結

    <a routerLink="/user/login">登入</a>
<a routerLink="/user/register">註冊</a>

路由守衛

路由守衛會告訴路由是否允許導航到請求的路由。

路由守方法可以返回 boolean 或 Observable \<boolean\> 或 Promise \<boolean\>，它們在將來的某個時間點解析為布林值

1、CanActivate

檢查使用者是否可以存取某一個路由。

CanActivate 為介面，路由守衛類要實現該介面，該介面規定類中需要有 canActivate 方法，方法決定是否允許存取目標路由。

路由可以應用多個守衛，所有守衛方法都允許，路由才被允許存取，有一個守衛方法不允許，則路由不允許被存取。

建立路由守衛：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 {
    // 用於實現跳轉
    return this.router.createUrlTree(["/user/login"])
    // 禁止存取目標路由
    return false
    // 允許存取目標路由
    return true
  }
}
{
  path: "about",
  component: AboutComponent,
  canActivate: [AuthGuard]
}

2、CanActivateChild

檢查使用者是否方可存取某個子路由。

建立路由守衛：ng g guard guards/admin

注意：選擇 CanActivateChild，需要將箭頭移動到這個選項並且敲擊空格確認選擇

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
    }
  ]
}

3、CanDeactivate

檢查使用者是否可以退出路由。比如使用者在表單中輸入的內容沒有儲存，使用者又要離開路由，此時可以呼叫該守衛提示使用者

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("有資料未儲存, 確定要離開嗎")) {
        return true
      } else {
        return false
      }
    }
    return true
  }

4、Resolve

允許在進入路由之前先獲取資料，待資料獲取完成之後再進入路由

$ 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: "張三" })
      }, 2000)
    })
  }
}
{
   path: "",
   component: HomeComponent,
   resolve: {
     user: ResolveGuard
   }
}
export class HomeComponent {
  constructor(private route: ActivatedRoute) {}
  ngOnInit(): void {
    console.log(this.route.snapshot.data.user)
  }
}

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