重点内容
for in 取 key; for of 取 value
for of 只能用于数组遍历,for in还可以用于对象属性的遍历
eg,
1. 遍历数组:
let array = [1,2,3,'lynn','Lanny']
console.log('for of: ')
for (let value of array){
console.log(value);
}
console.log('\n'+'for in: ')
for (let key in array){
console.log(key);
}
控制台打印
for of:
1
2
3
lynn
Lanny
for in:
0
1
2
3
4
1. 遍历对象:
function Person(){
this.name = 'Lanny';
this.age = '24';
this.sleep = ()=>{
console.log('I am sleeping~~~~');
}
}
Person.prototype.sayHello = (name)=>{
console.log('hello ' + name);
}
let person = new Person();
person.sayHello('Lynn');
for(let key in person){
if(person.hasOwnProperty(key)){ //不遍历原型方法
console.log(key);
}
}
控制台打印:
hello Lynn
name
age
sleep