How to use ES6 classes to imitate Vue and write a two-way binding-JS Tutorial-php.cn

This time I will show you how to use ES6 classes to imitate Vue to write a two-way binding. Use ES6 classes to imitate Vue to write a two-way binding.What are the precautions?What are the practical cases below? 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() } }

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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) } }) }

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Load input box event

this._initEvents('input, textarea', 'v-model', (i, key) => { i.addEventListener('input', () => { Object.assign(this.$data, {[key]: i.value}) }) })

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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})) })

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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)()) })

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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) } }) }

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Update the input box view

this._initView('input, textarea', 'v-model', (i, key, data) => { i.value = data })

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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') }) })

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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]) }) } })

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Listener (watcher)

Update after data changes View

 
 
 
  
您输入的是：{{text1}}+{{text2}}+{{text3}}
   您选择了：{{select}}

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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})) }) } }

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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!