最终效果如下：
构造器(constructor)
构造一个TinyVue对象，包含基本的el，data，methods
class TinyVue{ constructor({el, data, methods}){ this.$data = data this.$el = document.querySelector(el) this.$methods = methods // 初始化 this._compile() this._updater() this._watcher() } }
编译器(compile)
用于解析绑定到输入框和下拉框的v-model和元素的点击事件@click。
先创建一个函数用来载入事件：
// el为元素tagName，attr为元素属性（v-model，@click） _initEvents(el, attr, callBack) { this.$el.querySelectorAll(el).forEach(i => { if(i.hasAttribute(attr)) { let key = i.getAttribute(attr) callBack(i, key) } }) }
载入输入框事件
this._initEvents('input, textarea', 'v-model', (i, key) => { i.addEventListener('input', () => { Object.assign(this.$data, {[key]: i.value}) }) })
载入选择框事件
this._initEvents('select', 'v-model', (i, key) => { i.addEventListener('change', () => Object.assign(this.$data, {[key]: i.options[i.options.selectedIndex].value})) })
载入点击事件
点击事件对应的是methods中的事件
this._initEvents('*', '@click', (i, key) => { i.addEventListener('click', () => this.$methods[key].bind(this.$data)()) })
视图更新器(updater)
同理先创建公共函数来处理不同元素中的视图，包括input、textarea的value，select的选择值，div的innerHTML
_initView(el, attr, callBack) { this.$el.querySelectorAll(el, attr, callBack).forEach(i => { if(i.hasAttribute(attr)) { let key = i.getAttribute(attr), data = this.$data[key] callBack(i, key, data) } }) }
更新输入框视图
this._initView('input, textarea', 'v-model', (i, key, data) => { i.value = data })
更新选择框视图
this._initView('select', 'v-model', (i, key, data) => { i.querySelectorAll('option').forEach(v => { if(v.value == data) v.setAttribute('selected', true) else v.removeAttribute('selected') }) })
更新innerHTML
这里实现方法有点low，仅想到正则替换{{text}}
let regExpInner = /\{{ *([\w_\-]+) *\}}/g this.$el.querySelectorAll("*").forEach(i => { let replaceList = i.innerHTML.match(regExpInner) || (i.hasAttribute('vueID') && i.getAttribute('vueID').match(regExpInner)) if(replaceList) { if(!i.hasAttribute('vueID')) { i.setAttribute('vueID', i.innerHTML) } i.innerHTML = i.getAttribute('vueID') replaceList.forEach(v => { let key = v.slice(2, v.length - 2) i.innerHTML = i.innerHTML.replace(v, this.$data[key]) }) } })
监听器(watcher)
数据变化之后更新视图
<div> <input type="text" v-model="text1"><br> <input type="text" v-model="text2"><br> <textarea type="text" v-model="text3"></textarea><br> <button @click="add">加一</button> <h1>您输入的是：{{text1}}+{{text2}}+{{text3}}</h1> <select v-model="select"> <option value="volvo">Volvo</option> <option value="saab">Saab</option> </select> <select v-model="select"> <option value="volvo">Volvo</option> <option value="saab">Saab</option> </select> <h1>您选择了：{{select}}</h1> </div> <script src="https://www.jb51.net/article/TinyVue.js"></script> <script> let app = new TinyVue({ el: '#app', data: { text1: 123, text2: 456, text3: '文本框', select: 'saab' }, methods: { add() { this.text1 ++ this.text2 ++ } } }) </script>
TinyVue全部代码
class TinyVue{ constructor({el, data, methods}){ this.$data = data this.$el = document.querySelector(el) this.$methods = methods this._compile() this._updater() this._watcher() } _watcher(data = this.$data) { let that = this Object.keys(data).forEach(i => { let value = data[i] Object.defineProperty(data, i, { enumerable: true, configurable: true, get: function () { return value; }, set: function (newVal) { if (value !== newVal) { value = newVal; that._updater() } } }) }) } _initEvents(el, attr, callBack) { this.$el.querySelectorAll(el).forEach(i => { if(i.hasAttribute(attr)) { let key = i.getAttribute(attr) callBack(i, key) } }) } _initView(el, attr, callBack) { this.$el.querySelectorAll(el, attr, callBack).forEach(i => { if(i.hasAttribute(attr)) { let key = i.getAttribute(attr), data = this.$data[key] callBack(i, key, data) } }) } _updater() { this._initView('input, textarea', 'v-model', (i, key, data) => { i.value = data }) this._initView('select', 'v-model', (i, key, data) => { i.querySelectorAll('option').forEach(v => { if(v.value == data) v.setAttribute('selected', true) else v.removeAttribute('selected') }) }) let regExpInner = /\{{ *([\w_\-]+) *\}}/g this.$el.querySelectorAll("*").forEach(i => { let replaceList = i.innerHTML.match(regExpInner) || (i.hasAttribute('vueID') && i.getAttribute('vueID').match(regExpInner)) if(replaceList) { if(!i.hasAttribute('vueID')) { i.setAttribute('vueID', i.innerHTML) } i.innerHTML = i.getAttribute('vueID') replaceList.forEach(v => { let key = v.slice(2, v.length - 2) i.innerHTML = i.innerHTML.replace(v, this.$data[key]) }) } }) } _compile() { this._initEvents('*', '@click', (i, key) => { i.addEventListener('click', () => this.$methods[key].bind(this.$data)()) }) this._initEvents('input, textarea', 'v-model', (i, key) => { i.addEventListener('input', () => { Object.assign(this.$data, {[key]: i.value}) }) }) this._initEvents('select', 'v-model', (i, key) => { i.addEventListener('change', () => Object.assign(this.$data, {[key]: i.options[i.options.selectedIndex].value})) }) } }