数组扩展方法
includes()
检测数组中是否包含某个元素。
javascript
const arr = ['xiaoming', 'libai', 'anqila']
const res1 = arr.includes('xiaoming') // true
const res2 = arr.includes('sunshangxiang') // false
const arr = ['xiaoming', 'libai', 'anqila']
const res1 = arr.includes('xiaoming') // true
const res2 = arr.includes('sunshangxiang') // false
find()
查找数组中满足条件的那一项。
javascript
const arr = [
{
name: 'xiaoming',
age: 16
},
{
name: 'libai',
age: 17
},
{
name: 'anqila',
age: 18
}
]
const res = arr.find((item) => item.name === 'xiaoming') // {name: 'xiaoming', age: 16}
const arr = [
{
name: 'xiaoming',
age: 16
},
{
name: 'libai',
age: 17
},
{
name: 'anqila',
age: 18
}
]
const res = arr.find((item) => item.name === 'xiaoming') // {name: 'xiaoming', age: 16}
findIndex()
查找数据中满足条件的那一项的索引。
javascript
const arr = [
{
name: 'xiaoming',
age: 16
},
{
name: 'libai',
age: 17
},
{
name: 'anqila',
age: 18
}
]
const res = arr.findIndex((item) => item.name === 'xiaoming') // 0
const arr = [
{
name: 'xiaoming',
age: 16
},
{
name: 'libai',
age: 17
},
{
name: 'anqila',
age: 18
}
]
const res = arr.findIndex((item) => item.name === 'xiaoming') // 0
map()
遍历数组。
javascript
const arr = ['xiaoming', 'libai', 'anqila']
arr.map((item, index) => {
console.log(item, index) // 分别打印 xiaoming 0、libai 1、anqila 2
})
const arr = ['xiaoming', 'libai', 'anqila']
arr.map((item, index) => {
console.log(item, index) // 分别打印 xiaoming 0、libai 1、anqila 2
})
fill()
遍历数组。
javascript
new Array(3).fill('xiaoming') // ['xiaoming', 'xiaoming', 'xiaoming']
new Array(3).fill('xiaoming') // ['xiaoming', 'xiaoming', 'xiaoming']
sort()
数组排序。
javascript
const arr = ['b', 'a', 'c']
const arr2 = arr.sort((a, b) => (a > b ? 1 : -1)) // ['a', 'b', 'c']
const arr = ['b', 'a', 'c']
const arr2 = arr.sort((a, b) => (a > b ? 1 : -1)) // ['a', 'b', 'c']
filter()
数组过滤。
javascript
const arr = ['b', 'a', 'c']
const arr2 = arr.filter((x) => x !== 'a') // ['b', 'c']
const arr = ['b', 'a', 'c']
const arr2 = arr.filter((x) => x !== 'a') // ['b', 'c']
some()
判断数组中任意一项满足条件
javascript
const arr = ['b', 'a', 'c']
const res = arr.some((x) => x === 'a') // true
const arr = ['b', 'a', 'c']
const res = arr.some((x) => x === 'a') // true
every()
判断数组中所有项满足条件
javascript
const arr = ['b', 'a', 'c']
const res = arr.every((x) => x === 'a') // false
const arr = ['b', 'a', 'c']
const res = arr.every((x) => x === 'a') // false