JavaScript——iterator迭代

es6新特性

用iterator来遍历迭代Map，Set！

遍历数组

    // for in  下标
    var arr=[3,4,5]
    for (let x in arr){
        console.log(x)    //输出下标索引值
    }

 

    //for of  数组值 
    var arr=[3,4,5]
    for (var x of arr){
        console.log(x)    
    }

遍历map

var map=new Map([["Tom",100],["Jerry",90],["Alice",80]]);
    for (let x of map){
        console.log(x)
    }

遍历set

 var set=new Set([5,6,7]);
    for (let x of set) {
        console.log(x)
    }