Summarize
Avoid variable pollution, privatization, and save variable resident memory
the code
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>闭包</title>
</head>
<body>
</body>
<script>
// 闭包处理私有数据
let dealNum = function () {
let privateNum = 0
function changeNum(val) {
privateNum += val
}
return {
increment: function () {
changeNum(1)
},
decrement: function () {
changeNum(-1)
},
value: function () {
return privateNum
}
}
}
let a = dealNum()
// a.changeNum(1) // 报错
a.increment() // 1
console.log(a.value())
</script>
</html>