JavaScript Array function library

In fact, usually used more should be push and pop, but still remember, in order to use later.

Shift: Deletes the first item of the original array and returns the value of the deleted element; returns undefined if the array is empty
var a = [1,2,3,4,5];
var B = A.shift (); a:[2,3,4,5] B:1

Unshift: Adds a parameter to the beginning of the original array and returns the length of the array
var a = [1,2,3,4,5];
var B = A.unshift ( -2,-1); a:[-2,-1,1,2,3,4,5] B:7
Note: The test return value under IE6.0 is always undefined,ff2.0 Test return value is 7, so the return value of this method is not reliable, need to use the return value when the splice can be used instead of this method. This article from www.45it.com

Pop: Deletes the last item of the original array and returns the value of the deleted element; returns undefined if the array is empty
var a = [1,2,3,4,5];
var B = A.pop (); a:[1,2,3,4] B:5

Push: Adds a parameter to the end of the original array and returns the length of the array
var a = [1,2,3,4,5];
var B = A.push (6,7); a:[1,2,3,4,5,6,7] B:7

concat: Returns a new array that consists of adding parameters to the original array.
var a = [1,2,3,4,5];
var B = A.concat (6,7); a:[1,2,3,4,5] b:[1,2,3,4,5,6,7]

Splice(Start,deletecount,val1,val2,...) : Deletes the DeleteCount entry starting from the start position and inserts the Val1,val2 from that position,...
var a = [1,2,3,4,5];
var B = A.splice (2,2,7,8,9); a:[1,2,7,8,9,5] b:[3,4]
var B = a.splice (0,1); With shift
A.splice (0,0,-2,-1); var B = a.length; With Unshift
var B = A.splice (a.length-1,1); With pop
A.splice (a.length,0,6,7); var B = a.length; With push

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Splice Detailed:

The Splice function method removes one or more elements from an array and, if necessary, inserts a new element at the location of the removed element, returning the element that was removed.

　　arrayObj.splice( start, deleteCount, [item1[, item2[, . . . [,itemN]]]])

Where Arrayobj must be selected. An Array object.

Start is a required option. Specifies the starting position of the element to be removed from the array, which is calculated starting at 0.

DeleteCount is a mandatory option. The number of elements to remove.

Item1, item2,.. ., Itemn is a must-have option. The new element to insert at the location of the removed element.

The splice function method in JavaScript modifies arrayobj by removing the specified number of elements from the start position and inserting new elements. The return value is a new Array object that consists of the elements that were removed.

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Reverse : Reverse the array
var a = [1,2,3,4,5];
var B = A.reverse (); a:[5,4,3,2,1] b:[5,4,3,2,1]

Sort (orderfunction): Sorts the array by the specified parameters
var a = [1,2,3,4,5];
var B = A.sort (); a:[1,2,3,4,5] b:[1,2,3,4,5]

Slice (start,end): Returns a new array that consists of the entries from the original array that specify the starting subscript to the end subscript
var a = [1,2,3,4,5];
var B = a.slice (2,5); a:[1,2,3,4,5] b:[3,4,5]

Join (separator): Sets the element group of an array as a string, separator as a delimiter, or by default with a comma delimiter if omitted
var a = [1,2,3,4,5];
var B = A.join ("|"); a:[1,2,3,4,5] B: "1|2|3|4|5"

JavaScript Array function library