這次帶給大家使用ES6中class模仿Vue做出雙向綁定,使用ES6中class模仿Vue做出雙向綁定的注意事項有哪些,以下就是實戰案例,一起來看一下。
最終效果如下:
建構子(constructor)
建構一個TinyVue對象,包含基本的el,data,methods
class TinyVue{ constructor({el, data, methods}){ this.$data = data this.$el = document.querySelector(el) this.$methods = methods // 初始化 this._compile() this._updater() this._watcher() } }
編譯器(compile)
用於解析綁定到輸入框和下拉框的v-model和元素的點擊事件@ click。
先建立一個函數用來載入事件:
// el为元素tagName,attr为元素属性(v-model,@click) _initEvents(el, attr, callBack) { this.$el.querySelectorAll(el).forEach(i => { if(i.hasAttribute(attr)) { let key = i.getAttribute(attr) callBack(i, key) } }) }
載入輸入框事件
this._initEvents('input, textarea', 'v-model', (i, key) => { i.addEventListener('input', () => { Object.assign(this.$data, {[key]: i.value}) }) })
載入選擇框事件
this._initEvents('select', 'v-model', (i, key) => { i.addEventListener('change', () => Object.assign(this.$data, {[key]: i.options[i.options.selectedIndex].value})) })
載入點擊事件
點擊事件對應的是methods中的事件
this._initEvents('*', '@click', (i, key) => { i.addEventListener('click', () => this.$methods[key].bind(this.$data)()) })
#視圖更新器(updater)
同理先建立公用函數來處理不同元素中的視圖,包括input、textarea的value,select的選擇值,p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) } }) }
更新輸入框視圖
this._initView('input, textarea', 'v-model', (i, key, data) => { i.value = data })
更新選擇框視圖
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
這裡實作方法有點low,只想到正規取代{{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]) }) } })
監聽器(watcher)
資料變更之後更新視圖
<p id="app"> <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> </p> <script src="./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全部程式碼
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})) }) } }
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