<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>demo</title>
</head>
<body>
<div id="app">
</div>
</body>
<script>
let s = new Set([10, 20, 30]);
s.add(40);
s.add(30);
console.log(s);
s.delete(30);
console.log(s);
</script>
</html>
原文：http://www.cnblogs.com/linqitai/p/7411520.html