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obsever.js
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obsever.js
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class Observer {
constructor(value) {
this.value = value
this.walk(value)
}
walk (obj) {
const keys = Object.keys(obj)
for (let i = 0; i < keys.length; i++) {
this.defineReactive(obj, keys[i])
}
}
defineReactive (data, key) {
const dep = new Dep()
let val = data[key]
let childOb = observe(val)
Object.defineProperty(data, key, {
enumerable: true,
configurable: true,
get: function reactiveGetter () {
if (Dep.target) {
dep.depend()
}
return val
},
set: function reactiveSetter (newVal) {
val = newVal
childOb = observe(newVal)
dep.notify()
}
})
}
}
function observe (value, vm) {
if (!value || typeof value !== 'object') {
return
}
return new Observer(value)
}
var uid = 0;
class Dep {
constructor() {
this.id = uid++;
this.subs = [];
}
addSub (sub) {
this.subs.push(sub);
}
depend () {
Dep.target.addDep(this);
}
removeSub (sub) {
var index = this.subs.indexOf(sub);
if (index != -1) {
this.subs.splice(index, 1);
}
}
notify () {
this.subs.forEach(function (sub) {
sub.update();
});
}
}
Dep.target = null;