教你擼一個簡單的Vue

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

> obj.age
> 24

> obj.age = 25;
> 我改變了 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">改變值</button>
{{form}}
</div>

new Vue({
el: '#wrap',
data:{
form: '這是form的值',
test: '<strong>我是粗體</strong>',
},
methods:{
changeValue(){
console.log(this.form)
this.form = '值被我改變了，氣不氣？'
}
}
})

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

class Vue{
constructor(options = {}){
this.$el = document.querySelector(options.el);
let data = this.data = options.data; 
// 代理data，使其能直接this.xxx的方式訪問data，正常的話需要this.data.xxx
Object.keys(data).forEach((key)=> {
this.proxyData(key);
});
this.methods = options.methods // 事件方法
this.watcherTask = {}; // 需要監聽的任務列表
this.observer(data); // 初始化劫持監聽所有資料
this.compile(this.$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
// 批量更新檢視
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))
if(value.split('.').length > 1){
let v = null
value.split('.').forEach((val,i)=>{
v = !v ? this[val] : v[val]
})
return v
}else{
return this[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')
}

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

class Watcher{
constructor(el,vm,value,type){
this.el = el;
this.vm = vm;
this.value = value;
this.type = type;
this.update()
}
update(){
this.el[this.type] = this.vm.data[this.value]
}
}