ES6 for..of详解

es6新加了遍历方法for..of,今天看看怎么使用

 

遍历数组值

let arr=['red','green','blue','orange'];
for(let val of arr){
  console.log(val);
}

 

怎么把索引打印出来呢？

 

如果想要打印出索引可以这样

let arr=['red','green','blue','orange'];
for(let index of arr.keys()){
  console.log(index );//0,1,2,3
}

 

还可以这样

let arr=['red','green','blue','orange'];
for(let item of arr.entries()){
  console.log(item[0]);//red,green,blue,orange
}

 

能否key和value一块打印出来呢？

let arr=['red','green','blue','orange'];
for(let [key,val] of arr.entries()){
  console.log(key,val);
}

是不是很简单^_^

 

遍历对象

 

//Object.keys
let param = {
        name: "zhangsan",
        age: 21,
        sex: "male"
    };
for (let key of Object.keys(param)) {
     console.log(key);//name,age,sex
}

 

//Object.values
let param = {
        name: "zhangsan",
        age: 21,
        sex: "male"
    };

for (let value of Object.values(param)) {
     console.log(value);//zhangsan,21,male
}

 

//Object.entries
let param = {
        name: "zhangsan",
        age: 21,
        sex: "male"
    };

for (let [key,value] of Object.entries(param)) {
     console.log(key,value);//name "zhangsan", age 21, sex "male"
}