ES6 Set 和 Map

Set

Set的成员惟一

const set = new Set([1,2,4,6,4,1,2,4])

set.add("ff")

数组去重

const arr = [2,5,5,5,1,12,31,1,2]
[...new Set(arr)]

Array.from(arr)

• add
• clear
• delete
• has
• values
• keys
• entries (数组键值)
• forEach

WeakSet

只能接收引用类型

Map