实现一个vue-router

实现一个vue-router

myrouter.js
import HashHistory from "./hashHistory"
class VueRouter {
    constructor(options) {

        this.options = options

        // 如果不传mode，默认为hash
        this.mode = options.mode || 'hash'

        // 判断模式是哪种
        switch (this.mode) {
            case 'hash':
                this.history = new HashHistory(this)
                break
            case 'history':
                // this.history = new HTML5History(this, options.base)
                break
            case 'abstract':

        }
    }
    init(app) {
        this.history.listen((route) => app._route = route)

        // 初始化时执行一次，保证刷新能渲染
        this.history.transitionTo(window.location.hash.slice(1))
    }

    // 根据hash变化获取对应的所有组件
    createMathcer(location) {
        const { pathMap } = createRouteMap(this.options.routes)

        const record = pathMap[location]
        const local = {
            path: location
        }
        if (record) {
            return createRoute(record, local)
        }
        return createRoute(null, local)
    }
}

let _Vue
VueRouter.install = (Vue) => {
    _Vue = Vue
    // 使用Vue.mixin混入每一个组件
    Vue.mixin({
        // 在每一个组件的beforeCreate生命周期去执行
        beforeCreate() {
            if (this.$options.router) { // 如果是根组件
                // this 是 根组件本身
                this._routerRoot = this

                // this.$options.router就是挂在根组件上的VueRouter实例
                this.$router = this.$options.router

                // 执行VueRouter实例上的init方法，初始化
                this.$router.init(this)

                // 相当于存在_routerRoot上，并且调用Vue的defineReactive方法进行响应式处理
                Vue.util.defineReactive(this, '_route', this.$router.history.current)
            } else {
                // 非根组件，也要把父组件的_routerRoot保存到自身身上
                this._routerRoot = this.$parent && this.$parent._routerRoot
                // 子组件也要挂上$router
                this.$router = this._routerRoot.$router
            }
        }
    })
    Object.defineProperty(Vue.prototype, '$route', {
        get() {
            return this._routerRoot._route
        }
    })
}

function createRouteMap(routes) {

    const pathList = []
    const pathMap = {}

    // 对传进来的routes数组进行遍历处理
    routes.forEach(route => {
        addRouteRecord(route, pathList, pathMap)
    })

    console.log(pathList)
    // ["/home", "/home/child1", "/home/child2", "/hello", "/hello/child1"]
    console.log(pathMap)
    // {
    //     /hello: {path: xxx, component: xxx, parent: xxx },
    //     /hello/child1: {path: xxx, component: xxx, parent: xxx },
    //     /hello/child2: {path: xxx, component: xxx, parent: xxx },
    //     /home: {path: xxx, component: xxx, parent: xxx },
    //     /home/child1: {path: xxx, component: xxx, parent: xxx }
    // }


    // 将pathList与pathMap返回
    return {
        pathList,
        pathMap
    }
}

function addRouteRecord(route, pathList, pathMap, parent) {
    // 拼接path
    const path = parent ? `${parent.path}/${route.path}` : route.path
    const { component, children = null } = route
    const record = {
        path,
        component,
        parent
    }
    if (!pathMap[path]) {
        pathList.push(path)
        pathMap[path] = record
    }
    if (children) {
        // 如果有children，则递归执行addRouteRecord
        children.forEach(child => addRouteRecord(child, pathList, pathMap, record))
    }
}

function createRoute(record, location) {
    const res = []
    if (record) {
        while (record) {
            res.unshift(record)
            record = record.parent
        }
    }
    return {
        ...location,
        matched: res
    }
}
export default VueRouter

hashHistory.js
class HashHistory {
    constructor(router) {

        // 将传进来的VueRouter实例保存
        this.router = router

        // 一开始给current赋值初始值
        this.current = createRoute(null, {
            path: '/'
        })

        // 如果url没有 # ，自动填充 /#/ 
        ensureSlash()

        // 监听hash变化
        this.setupHashLister()
    }
    // 监听hash的变化
    setupHashLister() {
        window.addEventListener('hashchange', () => {
            // 传入当前url的hash
            this.transitionTo(window.location.hash.slice(1))
        })
    }

    // 跳转路由时触发的函数
    transitionTo(location) {
        console.log(location)
        
        // 找出所有对应组件
        let route = this.router.createMathcer(location)

        console.log(route)

        // hash更新时给current赋真实值
        this.current = route
        // 同时更新_route
        this.cb && this.cb(route)
    }
    // 监听回调
    listen(cb) {
        this.cb = cb
    }
}

// 如果浏览器url上没有#，则自动补充/#/
function ensureSlash() {
    if (window.location.hash) {
        return
    }
    window.location.hash = '/'
}

export function createRoute(record, location) {
    const res = []
    if (record) {
        while (record) {
            res.unshift(record)
            record = record.parent
        }
    }
    return {
        ...location,
        matched: res
    }
}

export default HashHistory

router-view组件
const myView = {
    functional: true,
    render(h, { parent, data }) {
        const { matched } = parent.$route

        data.routerView = true // 标识此组件为router-view
        let depth = 0 // 深度索引

        while(parent) {
            // 如果有父组件且父组件为router-view 说明索引需要加1
            if (parent.$vnode && parent.$vnode.data.routerView) {
                depth++
            }
            parent = parent.$parent
        }
        const record = matched[depth]

        if (!record) {
            return h()
        }

        const component = record.component

        // 使用render的h函数进行渲染组件
        return h(component, data)

    }
}
export default myView

router-link组件
const myLink = {
    props: {
        to: {
            type: String,
            required: true,
        },
    },
    // 渲染
    render(h) {

        // 使用render的h函数渲染
        return h(
            // 标签名
            'a',
            // 标签属性
            {
                domProps: {
                    href: '#' + this.to,
                },
            },
            // 插槽内容
            [this.$slots.default]
        )
    },
}

export default myLink

//学习自掘金林三心老师的代码