Array.prototype.splice()
The splice()
method changes the contents of an array by
removing or replacing existing elements and/or adding new elements in place. To access part of an array without modifying it, see slice()
.
Syntax
splice(start)
splice(start, deleteCount)
splice(start, deleteCount, item1)
splice(start, deleteCount, item1, item2, itemN)
Parameters
start
-
The index at which to start changing the array.
If greater than the length of the array,
start
will be set to the length of the array. In this case, no element will be deleted but the method will behave as an adding function, adding as many elements as items provided.If negative, it will begin that many elements from the end of the array. (In this case, the origin
-1
, meaning-n
is the index of then
th last element, and is therefore equivalent to the index ofarray.length - n
.) Ifstart
isnegative infinity
, it will begin from index0
. deleteCount
Optional-
An integer indicating the number of elements in the array to remove from
start
.If
deleteCount
is omitted, or if its value is equal to or larger thanarray.length - start
(that is, if it is equal to or greater than the number of elements left in the array, starting atstart
), then all the elements fromstart
to the end of the array will be deleted. However, it must not be omitted if there is anyitem1
parameter.If
deleteCount
is0
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 from
start
.If you do not specify any elements,
splice()
will only remove elements from the array.
Return value
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.
Description
If the specified number of elements to insert differs from the number of elements being removed, the array's length
will be changed.
Examples
Remove 0 (zero) elements before index 2, and insert "drum"
let myFish = ['angel', 'clown', 'mandarin', 'sturgeon']
let removed = myFish.splice(2, 0, 'drum')
// myFish is ["angel", "clown", "drum", "mandarin", "sturgeon"]
// removed is [], no elements removed
Remove 0 (zero) elements before index 2, and insert "drum" and "guitar"
let myFish = ['angel', 'clown', 'mandarin', 'sturgeon']
let removed = myFish.splice(2, 0, 'drum', 'guitar')
// myFish is ["angel", "clown", "drum", "guitar", "mandarin", "sturgeon"]
// removed is [], no elements removed
Remove 1 element at index 3
let myFish = ['angel', 'clown', 'drum', 'mandarin', 'sturgeon']
let removed = myFish.splice(3, 1)
// myFish is ["angel", "clown", "drum", "sturgeon"]
// removed is ["mandarin"]
Remove 1 element at index 2, and insert "trumpet"
let myFish = ['angel', 'clown', 'drum', 'sturgeon']
let 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"
let myFish = ['angel', 'clown', 'trumpet', 'sturgeon']
let removed = myFish.splice(0, 2, 'parrot', 'anemone', 'blue')
// myFish is ["parrot", "anemone", "blue", "trumpet", "sturgeon"]
// removed is ["angel", "clown"]
Remove 2 elements, starting from index 2
let myFish = ['parrot', 'anemone', 'blue', 'trumpet', 'sturgeon']
let removed = myFish.splice(2, 2)
// myFish is ["parrot", "anemone", "sturgeon"]
// removed is ["blue", "trumpet"]
Remove 1 element from index -2
let myFish = ['angel', 'clown', 'mandarin', 'sturgeon']
let removed = myFish.splice(-2, 1)
// myFish is ["angel", "clown", "sturgeon"]
// removed is ["mandarin"]
Remove all elements, starting from index 2
let myFish = ['angel', 'clown', 'mandarin', 'sturgeon']
let removed = myFish.splice(2)
// myFish is ["angel", "clown"]
// removed is ["mandarin", "sturgeon"]
Specifications
Specification |
---|
ECMAScript Language Specification # sec-array.prototype.splice |
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