緒論
寫JS方法會碰到參數不固定的時候,把每個參數都賦值又感覺麻煩,就想有沒有辦法設置個默認值呢?果然有解決方法。在此記錄一下。
正文
<!DOCTYPE html>
<div 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>index</title>
<script src="js/jquery-2.2.4.min.js"></script>
<style>
</style>
</head>
<body>
</body>
<script>
$(document).ready(function () {
Node1();
Node1(10);
Node1(10, null, null);
Node2();
Node2(10);
Node2(10, null, null);
// 參數必須爲{},否則報錯
Node3({});
Node3({data:10});
Node3({data:10, left:null, right:null});
// 可以沒有參數
Node4();
Node4({data:10});
Node4({data:10, left:null, right:null});
});
function Node1(data, left, right) {
console.log('Node1方法:data:' + data + ', left:' + left + ', right:' + right);
}
function Node2(data = 21, left = 22, right = 23) {
console.log('Node2方法:data:' + data + ', left:' + left + ', right:' + right);
}
function Node3({data = 31, left = 32, right = 33}) {
console.log('Node3方法:data:' + data + ', left:' + left + ', right:' + right);
}
function Node4({data = 41, left = 42, right = 43} = {}) {
console.log('Node4方法:data:' + data + ', left:' + left + ', right:' + right);
}
</script>
</div>
結果
(若有什麼錯誤,請留言指正,3Q)