实现代码:
class Vue { constructor(options) { //缓存参数 this.$options = options; //需要监听的数据 this.$data = options.data; //数据监听 this.observe(this.$data); } observe(value) { if (!value || typeof value !== 'object') { return; } /* 取到每个key和value 调用definReactive 进行数据劫持 */ Object.keys(value).forEach(key => { //深度监听 if (typeof value[key] === 'object') { this.observe(value[key]); } this.definReactive(value, key, value[key]); }) } definReactive(obj, key, val) { Object.defineProperty(obj, key, { get() { return val; }, set(newVal) { if (newVal === val) { return; } val = newVal; console.log(`${key}属性更新了:${val}`); } }) } }
测试代码:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<script src="./vue.js"></script>
<script>
const app = new Vue({
data: {
test: "i am test",
foo: {
bar: "bar"
}
}
});
app.$data.test = "hello world!!";
app.$data.foo.bar = "oh my bar";
</script>
</body>
</html>
测试结果:
