关于javascript:手写vuerouter核心原理

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最近也在察看 vue3 新个性，抽空玩一玩嵌套路由的 vue-router，间接上代码

app.vue

<template>
  <div id="app">
    <div>
      <router-link to="/">Index</router-link> |
      <router-link to="/person">Person</router-link> |
      <router-link to="/person/info">PersonInfo</router-link>
    </div>
    <!-- 一级路由 -->
    <router-view />
  </div>
</template>

<style>
#app{display: flex;  flex-direction: column;  align-items: center;}
</style>

Index.vue

<template>
  <div class="index">
    <h1>this is index page</h1>
  </div>
</template>

Person.vue

<template>
  <div class="person">
    <h1>this is person page</h1>
     <!-- 二级路由 -->
    <router-view />
  </div>
</template>

PersonInfo.vue

<template>
  <div class="personInfo">
    <h2>this is personInfo page</h2>
  </div>
</template>

main.js

import Vue from 'vue'
import App from './App.vue'
import router from './router'

new Vue({
  router,
  render: h => h(App)
}).$mount('#app')

babel.config.js
须要增加 babel 依赖反对新语法，如可选链
npm install --save-dev @babel/core @babel/cli
npm install --save-dev @babel/plugin-proposal-optional-chaining

module.exports = {presets: [    '@babel/preset-env'],
  plugins: ['@babel/plugin-proposal-optional-chaining']
}

router 目录下文件
index.js

import Vue from "vue";
import VueRouter from "./vue-router";
import Index from "../views/Index.vue";
import Person from "../views/Person.vue";
import PersonInfo from "../views/PersonInfo.vue";

Vue.use(VueRouter);

const routes = [
  {
    path: "/",
    name: "Index",
    component: Index
  },
  {
    path: "/person",
    name: "Person",
    component: Person,
    children:[
      {
        path: "/person/info",
        name: "PersonInfo",
        component: PersonInfo
      }
    ]
  }
];

const router = new VueRouter({routes});

export default router;

参考视频解说：进入学习

vue-router.js
这里先借助 Vue 的工具 Vue.util.defineReactive 实现数据响应式，后续再手撕这个库

import routerLink from "./router-link";
import routerView from "./router-view";

let Vue;
class VueRouter {constructor(options) {
    this.$options = options

    this.current = window.location.hash.slice(1) || "/"

    // 设置响应式数组数据
    Vue.util.defineReactive(this, "routerArray", [])

    // 监听 hash 值变动
    window.addEventListener("hashchange", this.hashChange.bind(this))

    this.getRouterArray()}

  hashChange() {this.current = window.location.hash.slice(1) || "/"
    this.routerArray = []
    this.getRouterArray()}

  getRouterArray(routes) {
    routes = routes || this.$options.routes
    for (const route of routes) {if (this.current === '/' && route.path === '/') {this.routerArray.push(route)
        return
      }

      if (this.current.indexOf(route.path) !== -1 && route.path !== '/') {this.routerArray.push(route)
        if (route.children) {
          // 递归子路由
          this.getRouterArray(route.children)
        }
        return
      }
    }
  }
}

VueRouter.install = function(_Vue) {
  Vue = _Vue

  // Vue 全局混入，等 new Vue 中的 router 实例创立之后挂载到 Vue 上
  Vue.mixin({beforeCreate() {if (this.$options.router) {Vue.prototype.$router = this.$options.router}
    },
  });

  // 注册 router-link 和 router-view 全局组件
  Vue.component("router-link", routerLink)
  Vue.component("router-view", routerView)
}

export default VueRouter

router-link.js

export default {
  props: {
    to: {
      type: String,
      required: true
    }
  },
  render(h) {
    return h(
      "a",
      {
        attrs: {href: "#" + this.to,},
      },
      this.$slots.default
    );
  }
};

router-view.js

export default {render(h) {
    // 设置嵌套路由标识
    this.$vnode.data.rv = true

    // 嵌套路由设置深度
    let depth = 0
    let parent = this.$parent
    while (parent) {

      // 下级还有嵌套路由标识 rv 为 true 的，深度加一
      if (parent.$vnode?.data?.rv) {depth++}
      parent = parent.$parent
    }

    // 简略解决
    const route = this.$router.routerArray[depth]
    return h(route?.component);
  }
};