<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>新型数据结构Map应用</title>
</head>
<body>

</body>
<script>
// 1、
// let num = 123;
// let arr =[1,2,3];
// let fun = function () {};
// let obj = {};
// const map1 = new Map();
// map1.set(num,"q1"),
// map1.set(arr,"q2");
// map1.set(fun,"q3");
// map1.set(obj,"q4");
// console.log(map1);
// console.log(map1.keys());
// for (const key of map1.keys()) {
// console.log(key);
// }

// 2、
const map2 = new Map([
["a1","1"],
["a2","2"],
["a3","3"]
]);
map2.set("a4","4");
map2.delete("a2");
console.log(map2.has("a2"));//false
console.log(map2);
let arr1 = [...map2.values()];//可以把所有的value转存到数组
console.log(arr1);
let arr2 = [...map2.keys()];//可以把所有的key转存到数组
console.log(arr2);
let arr3 = [...map2.entries()];//显示数组里面的所有内容
console.log(arr3);
for (const key of map2.keys()) {
console.log(key);
}
// 适用于集合类型
</script>
</html>