Remove, insert, update array with Array.prototype.splice()

The splice() method changes the contents of an array by removing existing elements and/or adding new elements.

SyntaxSection

array.splice(start[, deleteCount[, item1[, item2[, ...]]]])

ParametersSection

start

Index at which to start changing the array (with origin 0). If greater than the length of the array, actual starting index will be set to the length of the array. If negative, will begin that many elements from the end of the array (with origin -1) and will be set to 0 if absolute value is greater than the length of the array.

deleteCount Optional

An integer indicating the number of old array elements to remove.

If deleteCount is omitted, or if its value is larger than array.length - start (that is, if it is greater than the number of elements left in the array, starting at start), then all of the elements from start through the end of the array will be deleted.

If deleteCount is 0 or negative, no elements are removed. In this case, you should specify at least one new element (see below).

item1, item2, ... Optional

The elements to add to the array, beginning at the start index. If you don't specify any elements, splice() will only remove elements from the array.

Return valueSection

An array containing the deleted elements. If only one element is removed, an array of one element is returned. If no elements are removed, an empty array is returned.

DescriptionSection

If you specify a different number of elements to insert than the number you're removing, the array will have a different length at the end of the call.

ExamplesSection

Remove 0 (zero) elements from index 2, and insert "drum"Section

var myFish = ['angel', 'clown', 'mandarin', 'sturgeon'];
var removed = myFish.splice(2, 0, 'drum');

// myFish is ["angel", "clown", "drum", "mandarin", "sturgeon"] 
// removed is [], no elements removed

Remove 1 element from index 3Section

var myFish = ['angel', 'clown', 'drum', 'mandarin', 'sturgeon'];
var removed = myFish.splice(3, 1);

// removed is ["mandarin"]
// myFish is ["angel", "clown", "drum", "sturgeon"]

Remove 1 element from index 2, and insert "trumpet"Section

var myFish = ['angel', 'clown', 'drum', 'sturgeon'];
var removed = myFish.splice(2, 1, 'trumpet');

// myFish is ["angel", "clown", "trumpet", "sturgeon"]
// removed is ["drum"]

Remove 2 elements from index 0, and insert "parrot", "anemone" and "blue"Section

var myFish = ['angel', 'clown', 'trumpet', 'sturgeon'];
var removed = myFish.splice(0, 2, 'parrot', 'anemone', 'blue');

// myFish is ["parrot", "anemone", "blue", "trumpet", "sturgeon"] 
// removed is ["angel", "clown"]

Remove 2 elements from index 2Section

var myFish = ['parrot', 'anemone', 'blue', 'trumpet', 'sturgeon'];
var removed = myFish.splice(myFish.length - 3, 2);

// myFish is ["parrot", "anemone", "sturgeon"] 
// removed is ["blue", "trumpet"]

Remove 1 element from index -2Section

var myFish = ['angel', 'clown', 'mandarin', 'sturgeon'];
var removed = myFish.splice(-2, 1);

// myFish is ["angel", "clown", "sturgeon"] 
// removed is ["mandarin"]

Remove all elements after index 2 (incl.)Section

var myFish = ['angel', 'clown', 'mandarin', 'sturgeon'];
var removed = myFish.splice(2);

// myFish is ["angel", "clown"] 
// removed is ["mandarin", "sturgeon"]