Array method added in ES6

var arr=Array.of(10,20,30)//Array.of(10)
			var arr2=new Array(10)
			console.log(arr,arr2)

new function 1：

of（）

function ： Set array length

If there is only one parameter, it is the length of the array , If more than one , The length of the array is the number of elements

new function 2：

from（）

function ： Convert to array

The parameter is the data to be converted into an array, which is in front arr-map-set Common in

let arr = Array.from({
			  0: '1',
			  1: '2',
			  2: 3,
			  length: 3
			});
			console.log(arr); // ['1', '2', 3]	

Note that if you use objects to array

Object's key To convert to the subscript of the array

var  arr=[10,203,400,2,3,5,6]
			var  re=arr.find(function(el){
				console.log(111)
				if(el>100){return true}
			})

new function 3：

find（）

function ： lookup

By traversing the query conditions Stop until you find it Returns the value found

var arr=[1,23,5,56,{name:"bob"}]
			var re=arr.includes({name:"bob"})
			console.log(re)

new function 4：

includes（）

function ： Does it contain

Returns a Boolean value , Although the contents of the two objects are the same, they are not the same reference , So back false

var arr=[10,30,50]
			var re=arr.findIndex(function(el){
				if(el>20){return true}
			})
			console.log(re)

new function 5:

findIndex()

The function finds the element and returns the subscript and find Similar, but the return value is the subscript of the element in the array

var  arr=[10,203,4,100,3004,5]
			var arr2=arr.fill("hello",2,4)//2 3
			console.log(arr,arr2,arr==arr2)

new function 6：

fill（）

function ： Replace

The first parameter is the replaced element , The second is the starting position of replacement , The third is the end position of the replacement, but it is the left closed right open interval It is actually the end position -1

			var arr=[[10,20,30],40,50,[[60,70],80,[90,[110],100]]]
			var arr2=arr.flat(3)
			console.log(arr2)

new function 7：

flat（）

function ： Array dimension reduction

The parameter represents the number of dimension reduction

How to create your own method implementation flat function

var arr=[[10,20,30],40,50,[[60,70],80,[90,[110],100]]]
			Array.prototype.myflat=function(count=Infinity){
				var arr=[]
				for(var i=0;i<this.length;i++){
					// arr.push(this[i])
					if(this[i].constructor==Array&&count>0){
						// for(var j=0;j<this[i].length;j++){
						// 	arr.push(this[i][j])
						// }
						var newarr=this[i].myflat(count-1)
						for(var j=0;j<newarr.length;j++){
							arr.push(newarr[j])
						}												
					}else{
						arr.push(this[i])
					}				
				}
				return arr
			}
			var re2=arr.myflat(1)
			console.log(re2)