创建

var map=new Map();

赋值

map.set('a','1');
map.set('b','2');
map.set('c','3');
map.set('d','4');

取值

map.get('a');

删除

map.delete('a');

for of & map

for(var key of map){
console.log(key);
}
for(var [key,value] of map){
            console.log(key, value);
        }
}
for(var [a,b] of map.entries()){
            console.log(a,b);
        }
for(var key of map.keys()){
            console.log(key);
        }
 for(var val of map.values()){
            console.log(val);
        }