目标

自己实现轮子：数据响应式引擎

基石

属性拦截器

操作对象

Data

class Observer {    value: any;    dep: Dep;    vmCount: number;    constructor(value: any) {        this.value = value;        this.dep = new Dep();        this.vmCount = 0;        def(value, '__ob__', this);        if(Array.isArray(value)) {            augment(value, arrayMethods, arrayKeys);            this.observerArray(value);        }else {            this.walk(value);        }    },        walk(obj: Object) {        const keys = Object.keys(obj);        for (let i = 0; i < keys.length; i ++) {            defineReactive(obj, keys[i]);        }     },        observerArray (items: Array
    
     ) {        for (let i = 0; i< items.length; i++) {            observer(items[i]);        }    }}