基本用法
let arr = [1, 3, 5, 8] let arrFilter = arr.filter(ele => ele > 4) console.log(arrFilter) // [5, 8]
let arrObj = [{ name: 'aa', age: 13 }, { name: 'bb', age: 23 }, { name: 'cc', age: 18 }, { name: 'dd', age: 11 }, { name: 'ee', age: 28 }] let arrObjFilter = arrObj.filter(ele => ele.age > 18) console.log(arrObjFilter) // [{name: 'bb', age: 23}, {name: 'ee', age: 28}]
进阶用法
- 数组去重(有点过时)
let arr = [1, 2, 3, 2, 3, 4] let arrFilter = arr.filter((ele, index, arr) => { return arr.indexOf(ele) === index }) console.log(arrFIlter)
let arr = [1, 2, 3, 2, 3, 4] let arrFilter = [...new Set(arr)] console.log(arrFilter)
目前比较常用的方法是使用ES6的set完成,上面
- 数组中的空字符去除
let arr = ['1', '2', '3', '', null, undefined, ' ', '4'] let arrFilter = arr.filter((ele, index, arr) => { return ele && ele.trim() }) console.log(arrFIlter)
- 高级用法
结合map使用可以先过滤出符合条件的对象然后去除某些不需要的字段,比如:
// 需求: 年龄大于18的姓名 let arrObj = [{ name: 'aa', age: 13 }, { name: 'bb', age: 23 }, { name: 'cc', age: 18 }, { name: 'dd', age: 11 }, { name: 'ee', age: 28 }] let arrObjFilter = arrObj.filter(ele => ele.age > 18).map(ele => { return ele.name }) console.log(arrObjFilter) // ['bb', 'ee']
https://juejin.cn/post/6844903551886426119