JS遍历map结构

let map = new Map()
map.set('first','hellow')
map.set('second','world')
console.log(map) //Map(2) {"first" => "hellow", "second" => "world"}
for (let s of map.keys()) {
    console.log(s)//first second
}
for (let s of map.values()) {
    console.log(s)//hello world
}
for (let s of map.entries()) {
    console.log(s) //["first", "hellow"] ["second", "world"]
}

for (let [key, value] of map) {
    console.log(key, value) //"first", "hellow" 和 "second", "world"
}