Array.prototype.splice()
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
Thesplice() method ofArray instances changes the contents of an array byremoving or replacing existing elements and/or adding new elementsin place.
To create a new array with a segment removed and/or replaced without mutating the original array, usetoSpliced(). To access part of an array without modifying it, seeslice().
Try it
const months = ["Jan", "March", "April", "June"];months.splice(1, 0, "Feb");// Inserts at index 1console.log(months);// Expected output: Array ["Jan", "Feb", "March", "April", "June"]months.splice(4, 1, "May");// Replaces 1 element at index 4console.log(months);// Expected output: Array ["Jan", "Feb", "March", "April", "May"]Syntax
splice(start)splice(start, deleteCount)splice(start, deleteCount, item1)splice(start, deleteCount, item1, item2)splice(start, deleteCount, item1, item2, /* …, */ itemN)Parameters
startZero-based index at which to start changing the array,converted to an integer.
- Negative index counts back from the end of the array — if
-array.length <= start < 0,start + array.lengthis used. - If
start < -array.length,0is used. - If
start >= array.length, no element will be deleted, but the method will behave as an adding function, adding as many elements as provided. - If
startis omitted (andsplice()is called with no arguments), nothing is deleted. This is different from passingundefined, which is converted to0.
- Negative index counts back from the end of the array — if
deleteCountOptionalAn integer indicating the number of elements in the array to remove from
start.If
deleteCountis omitted, or if its value is greater than or equal to the number of elements after the position specified bystart, then all the elements fromstartto the end of the array will be deleted. However, if you wish to pass anyitemNparameter, you should passInfinityasdeleteCountto delete all elements afterstart, because an explicitundefinedgetsconverted to0.If
deleteCountis0or negative, no elements are removed.In this case, you should specify at least one new element (see below).item1, …,itemNOptionalThe 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
Thesplice() method is amutating method. It may change the content ofthis. If the specified number of elements to insert differs from the number of elements being removed, the array'slength will be changed as well. At the same time, it uses[Symbol.species] to create a new array instance to be returned.
If the deleted portion issparse, the array returned bysplice() is sparse as well, with those corresponding indices being empty slots.
Thesplice() method isgeneric. It only expects thethis value to have alength property and integer-keyed properties. Although strings are also array-like, this method is not suitable to be applied on them, as strings are immutable.
Examples
Remove 0 (zero) elements before index 2, and insert "drum"
const myFish = ["angel", "clown", "mandarin", "sturgeon"];const removed = myFish.splice(2, 0, "drum");// myFish is ["angel", "clown", "drum", "mandarin", "sturgeon"]// removed is [], no elements removedRemove 0 (zero) elements before index 2, and insert "drum" and "guitar"
const myFish = ["angel", "clown", "mandarin", "sturgeon"];const removed = myFish.splice(2, 0, "drum", "guitar");// myFish is ["angel", "clown", "drum", "guitar", "mandarin", "sturgeon"]// removed is [], no elements removedRemove 0 (zero) elements at index 0, and insert "angel"
splice(0, 0, ...elements) inserts elements at the start of the array likeunshift().
const myFish = ["clown", "mandarin", "sturgeon"];const removed = myFish.splice(0, 0, "angel");// myFish is ["angel", "clown", "mandarin", "sturgeon"]// no items removedRemove 0 (zero) elements at last index, and insert "sturgeon"
splice(array.length, 0, ...elements) inserts elements at the end of the array likepush().
const myFish = ["angel", "clown", "mandarin"];const removed = myFish.splice(myFish.length, 0, "sturgeon");// myFish is ["angel", "clown", "mandarin", "sturgeon"]// no items removedRemove 1 element at index 3
const myFish = ["angel", "clown", "drum", "mandarin", "sturgeon"];const removed = myFish.splice(3, 1);// myFish is ["angel", "clown", "drum", "sturgeon"]// removed is ["mandarin"]Remove 1 element at index 2, and insert "trumpet"
const myFish = ["angel", "clown", "drum", "sturgeon"];const 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"
const myFish = ["angel", "clown", "trumpet", "sturgeon"];const 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
const myFish = ["parrot", "anemone", "blue", "trumpet", "sturgeon"];const removed = myFish.splice(2, 2);// myFish is ["parrot", "anemone", "sturgeon"]// removed is ["blue", "trumpet"]Remove 1 element from index -2
const myFish = ["angel", "clown", "mandarin", "sturgeon"];const removed = myFish.splice(-2, 1);// myFish is ["angel", "clown", "sturgeon"]// removed is ["mandarin"]Remove all elements, starting from index 2
const myFish = ["angel", "clown", "mandarin", "sturgeon"];const removed = myFish.splice(2);// myFish is ["angel", "clown"]// removed is ["mandarin", "sturgeon"]Using splice() on sparse arrays
Thesplice() method preserves the array's sparseness.
const arr = [1, , 3, 4, , 6];console.log(arr.splice(1, 2)); // [empty, 3]console.log(arr); // [1, 4, empty, 6]Calling splice() on non-array objects
Thesplice() method reads thelength property ofthis. It then updates the integer-keyed properties and thelength property as needed.
const arrayLike = { length: 3, unrelated: "foo", 0: 5, 2: 4,};console.log(Array.prototype.splice.call(arrayLike, 0, 1, 2, 3));// [ 5 ]console.log(arrayLike);// { '0': 2, '1': 3, '3': 4, length: 4, unrelated: 'foo' }Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-array.prototype.splice |