基于JavaScript实现一个简单的Vue

var obj = {name:'wclimb'}
var age = 24
Object.defineProperty(obj,'age',{
enumerable: true, // 可枚举
configurable: false, // 不能再define
get () {
return age
},
set (newVal) {
console.log('我改变了',age +' -> '+newVal);
age = newVal
}
})
> obj.age
> 24
> obj.age = 25;
> 我改变了 24 -> 25
> 25

<div id="wrap"> 
 <p v-html="test"></p>
 <input type="text" v-model="form">
 <input type="text" v-model="form">
 <button @click="changeValue">改变值</button>
 {{form}}
</div>

class Vue{
constructor(){}
proxyData(){}
observer(){}
compile(){}
compileText(){}
}
class Watcher{
constructor(){}
update(){}
}

class Vue{
constructor(options = {}){
this.$el = document.querySelector(options.el);
let data = this.data = options.data;
// 代理data，使其能直接this.xxx的方式访问data，正常的话需要this.data.xxx
Object.keys(data).forEach((key)=> {
this.proxyData(key);
});
this.methods = obj.methods // 事件方法
this.watcherTask = {}; // 需要监听的任务列表
this.observer(data); // 初始化劫持监听所有数据
this.compile(this.$el); // 解析dom
}
}

class Vue{
constructor(options = {}){
......
}
proxyData(key){
let that = this;
Object.defineProperty(that, key, {
configurable: false,
enumerable: true,
get () {
return that.data[key];
},
set (newVal) {
that.data[key] = newVal;
}
});
}
}

class Vue{
constructor(options = {}){
......
}
proxyData(key){
......
}
observer(data){
let that = this
Object.keys(data).forEach(key=>{
let value = data[key]
this.watcherTask[key] = []
Object.defineProperty(data,key,{
configurable: false,
enumerable: true,
get(){
return value
},
set(newValue){
if(newValue !== value){
value = newValue
that.watcherTask[key].forEach(task => {
task.update()
})
}
}
})
})
}
}

set(newValue){
if(newValue !== value){
value = newValue
// 批量更新视图
that.watcherTask[key].forEach(task => {
task.update()
})
}
}

class Vue{
constructor(options = {}){
......
}
proxyData(key){
......
}
observer(data){
......
}
compile(el){
var nodes = el.childNodes;
for (let i = 0; i < nodes.length; i++) {
const node = nodes[i];
if(node.nodeType === 3){
var text = node.textContent.trim();
if (!text) continue;
this.compileText(node,'textContent')
}else if(node.nodeType === 1){
if(node.childNodes.length > 0){
this.compile(node)
}
if(node.hasAttribute('v-model') && (node.tagName === 'INPUT' || node.tagName === 'TEXTAREA')){
node.addEventListener('input',(()=>{
let attrVal = node.getAttribute('v-model')
this.watcherTask[attrVal].push(new Watcher(node,this,attrVal,'value'))
node.removeAttribute('v-model')
return () => {
this.data[attrVal] = node.value
}
})())
}
if(node.hasAttribute('v-html')){
let attrVal = node.getAttribute('v-html');
this.watcherTask[attrVal].push(new Watcher(node,this,attrVal,'innerHTML'))
node.removeAttribute('v-html')
}
this.compileText(node,'innerHTML')
if(node.hasAttribute('@click')){
let attrVal = node.getAttribute('@click')
node.removeAttribute('@click')
node.addEventListener('click',e => {
this.methods[attrVal] && this.methods[attrVal].bind(this)()
})
}
}
}
},
compileText(node,type){
let reg = /{{(.*)}}/g, txt = node.textContent;
if(reg.test(txt)){
node.textContent = txt.replace(reg,(matched,value)=>{
let tpl = this.watcherTask[value] || []
tpl.push(new Watcher(node,this,value,type))
return value.split('.').reduce((val, key) => {
return this.data[key];
}, this.$el);
})
}
}
}

if(node.hasAttribute('v-html')){
let attrVal = node.getAttribute('v-html');
this.watcherTask[attrVal].push(new Watcher(node,this,attrVal,'innerHTML'))
node.removeAttribute('v-html')
}

that.watcherTask[key].forEach(task => {
task.update()
})

that.watcherTask[key].forEach(task => {
task.update()
})