let food = new Map(); console.log(food); //Map{}
let food = new Map(); let fruit ={},cook=function(){},dessert="甜點"; food.set(fruit,'apple'); console.log(food); //Map{Object => {"apple"}}
let food = new Map(); let fruit ={},cook=function(){},dessert="甜點"; food.set(fruit,'apple'); food.set(cook,'fork'); food.set(dessert,'donut'); console.log(food); //Map{Object => {"apple"},function function=>"fork", "甜點"=>"donut"}
console.log(food.size); //3
console.log(food.get(fruit)); //apple console.log(food.get(cook)); //fork
food.delete(dessert); console.log(food.has(dessert)); //false
food.forEach((key,value) =>{ console.log('${key} = ${value}'); //[object object] = apple function cook(){} = fork })
food.clear(); console.log(food); //Map{}