1 基本区别
- includes()和indexOf()都是用来检查数组是否包含某些元素,includes()返回值是布尔值,indexOf()返回的是索引值,如果没有返回-1
let arr = [1,2,3]
arr.indexOf(0)
arr.indexOf(2)
arr.includes(2)
2 检查NAN和undefined
- indexOf()不能检查NAN
- includes()可以检查NAN
let arr = [NaN,]
arr.indexOf(NaN)
arr.indexOf(undefined)
arr.includes(NaN)
arr.includes(undefined)
3 检查-0和+0
- includes()和indexOf()没有区分-0和+0,在判断时,认为二者是相同的
console.log(+0 === -0)
let arr = [+0]
arr.includes(-0)
arr.indexOf(-0)
4 不能检查复杂数据类型
- 二者只能判断简单数据类型,对于对象、数组等复杂数据类型是不可以判断的
let arr = [{a:1},{a:2}]
arr.includes({a:1})
arr.indexOf({a:1})
5 indexOf()和includes()都可用于字符串,并且存在有隐式转换
let str = 'a1b2c3'
str.indexOf('2')
str.indexOf(1)
str.includes('2')
str.includes(1)