-
Notifications
You must be signed in to change notification settings - Fork 0
/
02-defProp.html
49 lines (40 loc) · 980 Bytes
/
02-defProp.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
<!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>
<div id="app"></div>
<script>
const obj = {}
function defineReactive(obj, key, val) {
// 对传入obj进行访问拦截
Object.defineProperty(obj, key, {
get() {
console.log('get ' + key);
return val
},
set(newVal) {
if (newVal !== val) {
console.log('set ' + key + ':' + newVal);
val = newVal
// 更新函数
update()
}
}
})
}
function update() {
app.innerText = obj.foo
}
defineReactive(obj, 'foo', '')
obj.foo = new Date().toLocaleTimeString()
setInterval(() => {
obj.foo = new Date().toLocaleTimeString()
}, 1000);
</script>
</body>
</html>