miniVueRouter

小米糖糖 11/14/2020 vue-routerminivue

# VueRouter 原理

利用 Vue 的响应式属性，保存当前路由
利用浏览器监听 hash 或者 url 变化，更新响应式的路由信息
利用 mixIn 给组件添加生命周期初始化路由
将用户配置的路由信息生成路由表并进行保存
注册 router-link router-view 组件，在内部通过当前路由信息匹配路由表从而进行渲染
嵌套路由，这个稍微比较麻烦，在源码中，路由表是嵌套递归的，每次匹配时会生成一个 match 数组，对应索引就是层级，在 route-view 中根据对应层级，展示对应组件

# mini 实现效果

# mini 实现代码

实现较为简单，并且只做了 hash 模式，未实现嵌套路由

index.html

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <script src="https://cdn.jsdelivr.net/npm/vue"></script>
  <!-- <script src="https://unpkg.com/vue-router@2.0.0/dist/vue-router.js"></script> -->
  <title>miniVueRouter</title>
</head>

<body>
  <div id="app">
    <h2>VueRouterDemo</h2>
    <router-link to='/'>home</router-link>
    <router-link to='/about'>about</router-link>
    <hr>
    <router-view></router-view>
  </div>
</body>
<script src="./router-link.js"></script>
<script src="./router-view.js"></script>
<script src="./miniVueRouter.js"></script>
<script src="./component.js"></script>
<script src="./app.js"></script>

</html>

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mini 版本引用了 vue，作为 router 原理简单讲解
文件进行了拆分，组件单独拆到对应的文件，分模块查看更加清晰

app.js 与正常使用一致，将 vuerouter 替换为官方的 VueRouter 可以正常运行

app.js

// 正常使用即可
Vue.use(VueRouter)
const router = new VueRouter({
  mode: "hash",
  routes: [
    { path: "/", component: Home },
    { path: "/about", component: About },
  ]
})


const app = new Vue({ el: "#app", router })

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component.js

const Home = {
  template: "<div>{{title}}</div>",
  data() { return { title: '这是Home' } }
}

const About = {
  template: "<div>{{title}}</div>",
  data() { return { title: '这是About' } }
}

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# 重要部分

miniVueRouter.js


let _Vue
class VueRouter {
  constructor(options) {
    this.$options = options
    this.init()
  }
  // 在源码里比这个复杂得多，通过 createMatcher 创建一个闭包， 返回一个 {match，addRoutes}
  // 其他地方用的都是 这个叫做matcher的对象，所以 才有了element-admin中动态路由的hach方式
  // 直接生成一个新的VueRouter 使用其matcher对正在使用的matcher进行一个替换 就做到了更新
  createMatcher(routes = []) {
    console.log(routes)
    this.pathObj = {}
    routes.forEach(({ path, component }) => {
      this.pathObj[path] = _Vue.extend(component)
    })
  }
  match(path) {
    path = path || this.current
    return this.pathObj[path]
  }
  initEvent() {
    const hashChange = e => {
      this.current = location.hash.slice(1) || '/'
    }
    window.addEventListener('hashchange', hashChange)
    hashChange()
  }
  init() {
    this.createMatcher(this.$options.routes)
    this.initEvent()
    Vue.util.defineReactive(this, 'current', '/')
  }
}


VueRouter.install = function (Vue, options) {
  _Vue = Vue
  Vue.mixin({
    beforeCreate() {
      if (this.$options.router) {
        Vue.prototype.$router = this.$options.router
        this.$router.init(this)
      }
    }
  })
  Vue.component('router-link', RouterLink)
  Vue.component('router-view', RouterView)
}

if (window && window.Vue) {
  Vue.use(VueRouter)
}

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在源码里比这个复杂得多，通过 createMatcher 创建一个闭包，返回一个 {match，addRoutes}
其他地方用的都是这个叫做 matcher 的对象，所以才有了 element-admin 中动态路由的 hach 方式
直接生成一个新的 VueRouter 使用其 matcher 对正在使用的 matcher 进行一个替换就做到了更新

router-link.js

const RouterLink = {
  functional: true,
  props: {
    to: { type: [String, Object], default: "" }
  },
  render(h, context) {
    const handleClick = (e) => {
      e.preventDefault()
      location.hash = context.props.to
      Vue.prototype.$router.current = context.props.to
    }
    return h('a', { attrs: { href: context.props.to }, on: { click: handleClick } }, context.children)
  }

}

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router-view.js

const RouterView = {
  functional: true,
  render(h, context) {
    const com = Vue.prototype.$router.match()
    return h(com)
  }
}

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# 部分源码

源码中处理嵌套部分

// router-view 的render  部分代码
  let depth = 0
    let inactive = false
    // 只要父组件不是根组件就继续遍历
    while (parent && parent._routerRoot !== parent) {
      const vnodeData = parent.$vnode ? parent.$vnode.data : {}
      // 只要发现routerView  就把深度加一。。。。以匹配嵌套路由
      if (vnodeData.routerView) {
        depth++
      }


    ...
    const matched = route.matched[depth]
    const component = matched && matched.components[name]

    ...

    return h(component, data, children)

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createMatcher 源码

export function createMatcher(routes: Array<RouteConfig>, router: VueRouter): Matcher {
  // 根据传递的routes  递归加入生成一个  path列表，并把*放在最后
  const { pathList, pathMap, nameMap } = createRouteMap(routes)

  // addRoutes就是继续加路由，，，
  function addRoutes(routes) {
    createRouteMap(routes, pathList, pathMap, nameMap)
  }

  function match(raw: RawLocation, currentRoute?: Route, redirectedFrom?: Location): Route {
    // 调用match的时候是新建一个route对象，该对象有一个matched    matched是通过recoed  由下至上parent 组成的数组  嵌套路由比较有用
    const location = normalizeLocation(raw, currentRoute, false, router)
    const { name } = location

    if (name) {
      //如果解析到了名字属性，直接通过名字查找    record
      const record = nameMap[name]
      if (process.env.NODE_ENV !== 'production') {
        warn(record, `Route with name '${name}' does not exist`)
      }
      if (!record) return _createRoute(null, location)
      const paramNames = record.regex.keys.filter((key) => !key.optional).map((key) => key.name)

      if (typeof location.params !== 'object') {
        location.params = {}
      }

      if (currentRoute && typeof currentRoute.params === 'object') {
        for (const key in currentRoute.params) {
          if (!(key in location.params) && paramNames.indexOf(key) > -1) {
            location.params[key] = currentRoute.params[key]
          }
        }
      }

      location.path = fillParams(record.path, location.params, `named route "${name}"`)
      return _createRoute(record, location, redirectedFrom)
    } else if (location.path) {
      location.params = {}
      for (let i = 0; i < pathList.length; i++) {
        const path = pathList[i]
        const record = pathMap[path]
        // 内部通过 record的正则表达式进行匹配 判断是不是目标路由  如果是  就通过record 生成新的$route
        // $route 不是  record   扩展了很多东西  比如  matched
        if (matchRoute(record.regex, location.path, location.params)) {
          return _createRoute(record, location, redirectedFrom)
        }
      }
    }
    // no match
    return _createRoute(null, location)
  }

  function redirect(record: RouteRecord, location: Location): Route {
    const originalRedirect = record.redirect
    let redirect = typeof originalRedirect === 'function' ? originalRedirect(createRoute(record, location, null, router)) : originalRedirect

    if (typeof redirect === 'string') {
      redirect = { path: redirect }
    }

    if (!redirect || typeof redirect !== 'object') {
      if (process.env.NODE_ENV !== 'production') {
        warn(false, `invalid redirect option: ${JSON.stringify(redirect)}`)
      }
      return _createRoute(null, location)
    }

    const re: Object = redirect
    const { name, path } = re
    let { query, hash, params } = location
    query = re.hasOwnProperty('query') ? re.query : query
    hash = re.hasOwnProperty('hash') ? re.hash : hash
    params = re.hasOwnProperty('params') ? re.params : params

    if (name) {
      // resolved named direct
      const targetRecord = nameMap[name]
      if (process.env.NODE_ENV !== 'production') {
        assert(targetRecord, `redirect failed: named route "${name}" not found.`)
      }
      return match(
        {
          _normalized: true,
          name,
          query,
          hash,
          params,
        },
        undefined,
        location
      )
    } else if (path) {
      // 1. resolve relative redirect
      const rawPath = resolveRecordPath(path, record)
      // 2. resolve params
      const resolvedPath = fillParams(rawPath, params, `redirect route with path "${rawPath}"`)
      // 3. rematch with existing query and hash
      return match(
        {
          _normalized: true,
          path: resolvedPath,
          query,
          hash,
        },
        undefined,
        location
      )
    } else {
      if (process.env.NODE_ENV !== 'production') {
        warn(false, `invalid redirect option: ${JSON.stringify(redirect)}`)
      }
      return _createRoute(null, location)
    }
  }

  function alias(record: RouteRecord, location: Location, matchAs: string): Route {
    const aliasedPath = fillParams(matchAs, location.params, `aliased route with path "${matchAs}"`)
    const aliasedMatch = match({
      _normalized: true,
      path: aliasedPath,
    })
    if (aliasedMatch) {
      const matched = aliasedMatch.matched
      const aliasedRecord = matched[matched.length - 1]
      location.params = aliasedMatch.params
      return _createRoute(aliasedRecord, location)
    }
    return _createRoute(null, location)
  }

  function _createRoute(record: ?RouteRecord, location: Location, redirectedFrom?: Location): Route {
    if (record && record.redirect) {
      return redirect(record, redirectedFrom || location)
    }
    if (record && record.matchAs) {
      return alias(record, location, record.matchAs)
    }
    return createRoute(record, location, redirectedFrom, router)
  }

  return {
    match,
    addRoutes,
  }
}

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可以看到接收的是用户配置的 routes，以及 router 实例
最终返回的是 match, addRoutes,
在 router 中使用的匹配相关都是使用的此对象
所以动态生成路由原理就是替换为新的 matcher

极简版Vue 极简版VueX

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Choose mode

miniVueRouter

miniVueRouter

# VueRouter 原理

# mini 实现效果

# mini 实现代码

# 重要部分

# 部分源码