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mvvm.html
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mvvm.html
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=`, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<div id='app'>
<input type="text" v-model='text'>
{{ text }}
</div>
<script>
function observe(obj, vm) {
Object.keys(obj).forEach(function(key) {
defineReactive(vm, key, obj[key]);
})
}
function defineReactive(obj, key, val) {
var dep = new Dep();
Object.defineProperty(obj, key, {
get: function() {
//添加订阅者watcher到主题对象Dep
if(Dep.target) dep.addSub(Dep.target);
return val;
},
set: function(newVal) {
if(newVal === val) return;
val = newVal;
//作为发布者发出通知
dep.notify();
console.log(val);
}
});
}
function nodeToFragment(node, vm) {
var flag = document.createDocumentFragment();
var child;
while(child = node.firstChild) {
compile(child, vm);
flag.appendChild(child); //将子节点劫持到文档片段中
}
return flag;
}
function compile(node, vm) {
var reg = /\{\{(.*)\}\}/;
//节点类型为元素
if(node.nodeType === 1) {
var attr = node.attributes;
//解析属性
for(var i = 0; i<attr.length;i++) {
if(attr[i].nodeName == 'v-model') {
var name = attr[i].nodeValue; //获取v-model绑定的属性名
node.addEventListener('input', function(e) {
//给相应的data属性赋值，进而触发该属性的set方法
vm[name] = e.target.value;
});
node.value = vm[value]; //将data的值赋给该node
node.removeAttribute('v-model');
}
};
new Watcher(vm, node, name, 'input');
}
//节点类型为text
if(node.nodeType === 3) {
if(reg.test(node.nodeValue)) {
var name = RegExp.$1;
name = name.trim();
new Watcher(vm, node, name, 'text');
}
}
}
function Watcher(vm, node, name, nodeType) {
Dep.target = this;
this.name = name;
this.node = node;
this.vm = vm;
this.nodeType= nodeType;
this.update();
Dep.target = null;
}
Watcher.prototype = {
update: function() {
this.get();
if(this.nodeType == 'text') {
this.node.nodeValue = this.value;
}
if(this.nodeType == 'input') {
this.node.value = this.value;
}
},
//获取data中的属性值
get: function() {
this.value = this.vm[this.name]; //触发相应属性的get
}
}
function Dep() {
this.subs = []
}
Dep.prototype = {
addSub: function(sub) {
this.subs.push(sub);
},
notify: function() {
this.subs.forEach(function(sub) {
sub.update();
});
}
}
function Vue(options) {
this.data = options.data;
var data = this.data;
observe(data, this);
var id = options.el;
var dom = nodeToFragment(document.getElementById(id), this);
//编译完成后，将dom返回到app中
document.getElementById(id).appendChild(dom);
}
var vm = new Vue({
el: 'app',
data: {
text: 'hello world'
}
})
</script>
</body>
</html>