This time I will bring you ES6 to imitate Vue to implement the two-way binding function. What are the precautions for ES6 to imitate Vue to implement the two-way binding function. The following is a practical case, let’s take a look.
The final effect is as follows:
Constructor (constructor)
Constructs a TinyVue object, including basic el, data, methods
class TinyVue{
constructor({el, data, methods}){
this.$data = data
this.$el = document.querySelector(el)
this.$methods = methods
// 初始化
this._compile()
this._updater()
this._watcher()
}
}Compiler(compile)
Used to parse click events of v-model and elements bound to input boxes and drop-down boxes@ click.
First create a function to load events:
// el为元素tagName，attr为元素属性（v-model，@click）
_initEvents(el, attr, callBack) {
this.$el.querySelectorAll(el).forEach(i => {
if(i.hasAttribute(attr)) {
let key = i.getAttribute(attr)
callBack(i, key)
}
})
}Load input box event
this._initEvents('input, textarea', 'v-model', (i, key) => {
i.addEventListener('input', () => {
Object.assign(this.$data, {[key]: i.value})
})
})Load selection box event
this._initEvents('select', 'v-model', (i, key) => {
i.addEventListener('change', () => Object.assign(this.$data, {[key]: i.options[i.options.selectedIndex].value}))
})Load click Event
The click event corresponds to the event in methods
this._initEvents('*', '@click', (i, key) => {
i.addEventListener('click', () => this.$methods[key].bind(this.$data)())
})View updater(updater)
In the same way, first create a public function to handle different The view in the element includes the value of input and textarea, the selection value of select, and the innerHTML of p
_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)
}
})
}Update the input box view
this._initView('input, textarea', 'v-model', (i, key, data) => {
i.value = data
})Update the selection box view
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')
})
})Update innerHTML
The implementation method here is a bit low, I only think of regular replacement {{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])
})
}
})Listener (watcher)
Update after data changes View
<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 all code
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.$data, {[key]: i.options[i.options.selectedIndex].value}))
})
}
}I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!
Recommended reading:
jQuery$. and $(). Detailed explanation of usage
v-cloak is refreshing in vue How to deal with flickering when loading
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