ES6 Small Experiment-review arrays

ES6 to add a lot of methods to the array, I first summarize the previous method:
1.array.isarray (): Detecting arrays

var arr = ['a','b','C' ]var'abc'console.log (Array.isarray (arr)) // trueconsole.log (Array.isarray (str))//false

2.push (): Receive any number of parameters and add them to the end of the array one by one

 var  arr = [ " a   ", "  b   ", "  c      var  item = Arr.push ( '   

3.pop (): Removes the last item from the end of the array

var arr = [' A ', ' B ', ' C ']var item = arr.pop () console.log (item)//C Console.log (arr)//["A", "B"]

4.shift (): Removes the first item of an array and returns the item

var arr = [' A ', ' B ', ' C ']var item = arr.shift () console.log (item)// aconsole.log (arr)//

5.unshift (): Ability to add any item to the front of the array and return the new array length

var arr = [' A ', ' B ', ' C ']var item = arr.unshift (' d ', ' e ') console.log (item)//  5console.log (arr)//["D", "E", "A", "B", "C"]

6.reverse (): Reverses the order of the data items, noting that it has changed the original array

var arr = [2,4,6,3,1]console.log (Arr.reverse ())//[1, 3, 6, 4, 2]Console.log ( ARR)//[1, 3, 6, 4, 2]

7.sort (): Can receive a comparison function as a parameter, the comparison function receives two parameters, if the first parameter should be located before the second parameter will return a negative number, two parameters equal to return 0, if the first parameter should be located after the second parameter will return a positive number

var arr = [2,4,6,3,1]arr.sort (function(b) {    return A- B}) Console.log (arr)//[1, 2, 3, 4, 6]

8.concat (): Creates a new array based on all the items in the current array, feeling that the string is manipulated in a similar way

var arr1 = [' A ', ' B ', ' C ']var arr2 = [' d ', ' e ', ' F ']var arr = Arr1.concat ( ARR2) Console.log (arr)//["A", "B", "C", "D", "E", "F"]Console.log (arr1)//["A", "B "," C "]

9.slice (): Intercepts the original array, constructs a new array, and the original array remains unchanged

var arr = [' A ', ' B ', ' C ', ' d ', ' E ']var arr1 = Arr.slice (2)var arr2 = Arr.slice (2,3) console.log (arr1) // ["C", "D", "E"]console.log (ARR2)//["C"]

10.splice (): This is probably the most powerful array method, add, delete, change, Operation Almighty

(1) Increase, you can insert any number of items to the specified location, just provide three parameters, starting position, 0 (number of items to delete) and the item to be inserted

var arr = [' A ', ' B ', ' C ']arr.splice (1,0, ' d ', ' e ') console.log (arr)//  ["A", "D", "E", "B", "C"]

(2) by deleting, provide two parameters, the position of the first item to be deleted and the number of items to be deleted

var arr = [' A ', ' B ', ' C ', ' d ']arr.splice (console.log) (arr)//["A", "D"] 

(3) Change, combined with the above two ways, the first to delete and then increase is to change

var arr = [' A ', ' B ', ' C ', ' d ', ' E ']arr.splice (, ' f ', ' G ') Console.log (arr)//[ "A", "F", "G", "D", "E"]

11.indexOf (), lastIndexOf () They all receive two parameters, the index of the item to find and the location of the lookup starting point (optional), indexOf () to look backwards from the beginning, lastIndexOf looking forward from the end

var arr = [' A ', ' B ', ' C ', ' d ', ' C ', ' E ']console.log (Arr.indexof (' C ', 3))//4 Console.log (Arr.lastindexof (' C ', 3))//2

12.every (): Runs the given function for each item in the array, and returns True if the function returns true for each item

var num = [1,2,3,4,5,6]var everyresult = Num.every (function(item, Index, Array) {    return (item > 0)}) Console.log (everyresult)//True 

13.filter (): Each item in an array runs the given function, and returns the list of items that the function returns True

var num = [1,2,3,4,5,6]var filterresult = Num.filter (function(item, Index, Array) {    return (item > 3)}) Console.log (filterresult)//[4, 5, 6]

14.forEach (): Runs the given function for each item in the array, this method does not return a value

var num = [1,2,3,4,5,6]num.foreach (function(item, index, array) {    Console.log (item)//1,2,3,4,5,6})

15.map (): Each item in an array runs the given function, and returns a list of the results of each function call

var num = [1,2,3,4,5,6]var mapresult = Num.map (function(item, index, array) {     return Item * 2}) Console.log (mapresult)//[2, 4, 6, 8, ten, each]

16.some (): Runs the given function for each item in the array and returns TRUE if the function returns true for either item

var num = [1,2,3,4,5,6]var someresult = Num.some (function(item, index, array) {     return item > 5}) Console.log (someresult)//true

17.reduce (), Reduceright (): Iterates through all the items of an algebraic group, and then constructs a final returned value, reduce () starting with the first item, Reduceright () starting with the last item

var num = [1,2,3,4,5,6]var reduceresult = Num.reduce (function(prev, cur, index , array) {    return prev + cur}) console.log (reduceresult)//

ES6 Small Experiment-review arrays