1.forEach
let arr = [‘aaa‘, ‘bbb‘, ‘ccc‘] arr.forEach((item, index, array) => { console.log(val, index, arr) })
类似于，for循环
2.map
正常情况下，需要配合return来返回一个新的数组，如果没有return， 则相当于forEach
let arr = [ {name: ‘小明‘, sex: ‘男‘, age: 15}, {name: ‘小红‘, sex: ‘女‘, age: 13}, {name: ‘小东‘, sex: ‘男‘, age: 17}, {name: ‘小强‘, sex: ‘男‘, age: 14} ] let newArr = arr.map((item, index, array) => { if (item.age > 16) { return item.name + ‘已成年‘ } else { return item.name + ‘未成年‘ } }) console.log(newArr)
3.filter
过滤， 返回一个新的数组
let arr = [ {name: ‘小明‘, sex: ‘男‘, age: 15}, {name: ‘小红‘, sex: ‘女‘, age: 13}, {name: ‘小东‘, sex: ‘男‘, age: 17}, {name: ‘小强‘, sex: ‘男‘, age: 14} ] let newArr = arr.filter((item, index, array) => {return item.age < 16 }) console.log(newArr)
4.some
按照我的理解就是判断数组中是否有满足条件的项
let arr = [ {name: ‘小明‘, sex: ‘男‘, age: 15}, {name: ‘小红‘, sex: ‘女‘, age: 13}, {name: ‘小东‘, sex: ‘男‘, age: 17}, {name: ‘小强‘, sex: ‘男‘, age: 14} ] let newArr = arr.some((item, index, array) => { return item.age < 16 }) console.log(newArr)
5.every
判断数组中是否每一项都满足条件
let arr = [
{name: ‘小明‘, sex: ‘男‘, age: 15},
{name: ‘小红‘, sex: ‘女‘, age: 13},
{name: ‘小东‘, sex: ‘男‘, age: 17},
{name: ‘小强‘, sex: ‘男‘, age: 14}
]
let newArr = arr.every((item, index, array) => {
return item.age < 16
})
console.log(newArr)
6.reduce
类似于递归函数，从左往右循环
let arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
let res = arr.reduce((prev, cur, index, array) => {
return prev + cur
})
console.log(res)
7、reducerRight
类似于递归函数，从右往左循环
原文：https://www.cnblogs.com/wylj/p/10635348.html