js中Array对象的常用遍历方法详解
时间：2021-08-10 09:24:15|栏目：JavaScript代码|点击： 次
1.forEach(),遍历数组的每个元素
let arrFor = ['muzi','digbig','muzidigbig','lucky']
//forEach(),遍历数组的每个元素
arrFor.forEach((item,index) => {
console.log(`${index}---${item}`)
})
2.map(参数为回调函数)函数，遍历数组每个元素，并回调操作，需要返回值，返回值组成新数组，原数组不变；
let arr = [{id:1,name:'muzi'},{id:2,name:'digbig'},{id:3,name:'muzidigbig'},{id:4,name:'lucky'}]
const arrMap = arr.map((item,index) => {
return {
id:item.id,
name:item.name,
sex:'男'
}
})
console.log(arrMap)
3.filter(参数为回调函数)函数：过滤通过条件的元素组成一个新数组，原数组不变；
let arr = [{id:1,name:'muzi'},{id:2,name:'digbig'},{id:3,name:'muzidigbig'},{id:4,name:'lucky'}]
const arrFilter = arr.filter((item,index) => {
return item.id >= 2;
})
console.log(arrFilter)
4.some(参数为回调函数)函数，遍历数组中是否有符合条件的函数，返回布尔值；
let arr = [{id:1,name:'muzi'},{id:2,name:'digbig'},{id:3,name:'muzidigbig'},{id:4,name:'lucky'}]
const arrSome = arr.some((item,index) => {
return item.id === 5
})
console.log(arrSome)
5.every(参数为回调函数)函数，遍历数组是否每个元素都符合条件，返回布尔值；
let arr = [{id:1,name:'muzi'},{id:2,name:'digbig'},{id:3,name:'muzidigbig'},{id:4,name:'lucky'}]
const arrEvery = arr.every((item,index) => {
return item.id >= 1
})
console.log(arrEvery)
6.find()函数，数组中的每个元素都执行这个回调函数；返回第一个满足条件的元素 之后的元素就不在调用；没有符合的返回undefined；并没有改变数组的原始值。
let arr = [{id:1,name:'muzi'},{id:2,name:'digbig'},{id:3,name:'muzidigbig'},{id:4,name:'lucky'}]
const arrFind = arr.find((item,index) => {
return item.id === 1
})
console.log(arrFind)
7.reduce(),合并二维数组
var twoArr = [['mu','zi'],['dig','big'],['lucky','jiji']];
var oneArr = twoArr.reduce(function(total,currentValue){
// console.log(total)
return total.concat(currentValue);
},[])
console.log(oneArr);//["mu", "zi", "dig", "big", "lucky", "jiji"]
总结
