js怎么定义map

let a=new Map();

let b={p:'Hello World'};

a.set(b,"content");

a.get(b);               //"content"

a.has(b)                //true

a.delete(b)             //true

a.has(b)                //false

let map=new Map(['first','aaaaaa'],['second','bbbbbb']);;

map.size();             //2

map.has('first');       //true

a.get(b);               //'aaaaaa'

map.has('second');      //true

a.get(b);               //'bbbbbb'