06数组拓展-es6

# 数组拓展

//Array.from() 把类数组转化成数组
function fn(){
  console.log(Array.from(arguments))
}
fn(1,2,3)

//Array.of 将一组值，转换为数组
console.log(Array.of(3, 11, 8)) // [3,11,8]

//find() 找出第一个符合条件的数组成员
let arr = [1,2,3,4,5]
let newArr = arr.find(function(item){
  return item % 2 === 0
})
console.log(newArr)//2

//findIndex() 找出第一个符合条件的数组成员的索引值
let arr = [1,2,3,4,5]
let newArr = arr.findIndex(function(item){
  return item % 2 === 0
})
console.log(newArr)//1

//fill() 填充数组
console.log(['a', 'b', 'c'].fill(7))//[7, 7, 7]
console.log([,,,].fill(6))//[6,6,6]

//flat() 数组扁平化
let arr = [['name', '小明'], ['age', 18], ['sex', '男']]
console.log(arr.flat(1))//["name","小明","age",18,"sex","男"]

let arr = [1,2,[3,4,[5,6]]]
 console.log(arr.flat(Infinity))//永远变成1维数组

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[!cogs]

%accordion% 把类数组转化成数组 %accordion%

function fn() {
    console.log([...arguments]); //[1, 2, 3]
    // console.log(Array.from(arguments)); //[1, 2, 3]
}
fn(1, 2, 3)


//Array.of 将一组值，转换为数组
console.log(Array.of(3, 11, 8)) // [3,11,8]

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//find() 找出第一个符合条件的数组成员
let arr = [1, 2, 3, 4, 5]
let newArr = arr.find(function (item) {
    return item % 2 === 0
})
console.log(newArr)//2

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%/accordion%

# 数组扁平化✨

//flat() 数组扁平化
let arr = [
    ['name', '小明'],
    ['age', 18],
    ['sex', '男']
]
console.log(arr.flat(1)) //["name","小明","age",18,"sex","男"]


//flat() 数组扁平化
//Infinity永远都是一维
let arr = [
    [1, 2, [3, 4, [5, 6]]]
]
console.log(arr.flat(Infinity)) //[1, 2, 3, 4, 5, 6]

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编辑

上次更新: 2022/04/24, 13:33:34

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