利用js的defineProperty方法，setter/getter。
<!DOCTYPE html>
<head>
<title>myVue</title>
</head>
<body>
<div id="app">
<form>
<input type="text" v-model="number" />
<button type="button" v-click="increase">Add</button>
</form>
<h3 v-bind="number"></h3>
</div>
</body>
<script>
function myVue(options) {
this._init(options)
}
myVue.prototype._init = function (options) {
this.$options = options
this.$el = document.querySelector(options.el)
this.$data = options.data
this.$methods = options.methods
this._bindings = {}
this._obverse(this.$data)
this._compile(this.$el)
}
myVue.prototype._obverse = function (obj) {
var value
for (key in obj) {
if (obj.hasOwnProperty(key)) {
this._bindings[key] = {
_directives: []
}
value = obj[key]
if (typeof value === 'object') {
this._obverse(value)
}
var binding = this._bindings[key]
Object.defineProperty(this.$data, key, {
enumerable: true,
configurable: true,
get: function () {
return value
},
set: function (newVal) {
if (value !== newVal) {
value = newVal
}
binding._directives.forEach(function (item) {
item.update()
})
}
})
}
}
}
myVue.prototype._compile = function (root) {
var _this = this
var nodes = root.children
for (var i = 0; i < nodes.length; i++) {
var node = nodes[i]
if (node.children.length) {
this._compile(node)
}
if (node.hasAttribute('v-click')) {
node.onclick = (function() {
var attrVal = nodes[i].getAttribute('v-click')
return _this.$methods[attrVal].bind(_this.$data)
})()
}
if (node.hasAttribute('v-model') && (node.tagName === 'INPUT' || node.tagName === 'TEXTAREA')) {
node.addEventListener('input', (function(key) {
var attrVal = node.getAttribute('v-model')
_this._bindings[attrVal]._directives.push(new Watcher(
'input',
node,
_this,
attrVal,
'value'
))
return function () {
_this.$data[attrVal] = nodes[key].value
}
})(i))
}
if (node.hasAttribute('v-bind')) {
var attrVal = node.getAttribute('v-bind')
_this._bindings[attrVal]._directives.push(new Watcher(
'text',
node,
_this,
attrVal,
'innerHTML'
))
}
}
}
function Watcher(name, el, vm, exp, attr) {
this.name = name
this.el = el
this.vm = vm
this.exp = exp
this.attr = attr
this.update()
}
Watcher.prototype.update = function () {
this.el[this.attr] = this.vm.$data[this.exp]
}
window.onload = function () {
var app = new myVue({
el: '#app',
data: {
number: 0
},
methods: {
increase: function () {
this.number ++
}
}
})
}
</script>
