How to use the slice method of Arrays in Javascript?

What does slice() do in JavaScript?

Short answer: array.slice(start, end) returns a new array with the items from start up to end, without including end. The original array doesn't change. Negative numbers count from the end, so slice(-2) gives the last two items.

const fruits = ["apple", "banana", "cherry", "kiwi"];
 
fruits.slice(1, 3);   // ["banana", "cherry"]
fruits.slice(-2);     // ["cherry", "kiwi"]
console.log(fruits);  // ["apple", "banana", "cherry", "kiwi"]  unchanged

Don't confuse it with splice(), which removes items from the original array.

slice() copies a range without the end position, counts from the end with negative numbers and never changes the original array.

slice() at a glance

Syntax of slice()

array.slice()
array.slice(start)
array.slice(start, end)

• start (optional): the first position to copy. By default 0.
• end (optional): where to stop. This position is not included. By default, the end of the array.

Both accept negative numbers: -1 is the last position, -2 the one before it. If start is greater than end, or beyond the length, you get an empty array: fruits.slice(3, 1) is [].

slice() vs splice()

The names are similar, but they do very different things:

const nums = [1, 2, 3, 4, 5];
 
console.log(nums.slice(1, 3));    // [2, 3]
console.log(nums);                // [1, 2, 3, 4, 5]
 
console.log(nums.splice(1, 2));   // [2, 3]
console.log(nums);                // [1, 4, 5]

If you want splice() without changing the original, use toSpliced(), available in current browsers and Node.js 20 or newer.

Get the first or last items

const scores = [90, 85, 77, 64, 58];
 
scores.slice(0, 3);    // [90, 85, 77]  top 3
scores.slice(-2);      // [64, 58]      last 2
scores.slice(1);       // [85, 77, 64, 58]  all except the first
scores.slice(0, -1);   // [90, 85, 77, 64]  all except the last

For a single item, scores.at(-1) returns 58 directly, without an array.

Copy an array with slice()

slice() with no arguments copies the whole array. Changing the copy doesn't change the original:

const original = [1, 2, 3];
const copy = original.slice();
copy.push(4);
 
console.log(original);   // [1, 2, 3]
console.log(copy);       // [1, 2, 3, 4]

It's a shallow copy: objects inside are shared, so changing copy[0].name also changes the original. For a deep copy, use structuredClone(original).

Paginate a list

const items = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
const pageSize = 3;
const page = 2;
 
const pageItems = items.slice((page - 1) * pageSize, page * pageSize);
console.log(pageItems);   // [4, 5, 6]

slice() doesn't fail if the end goes past the length, so the last page simply has fewer items.

slice() with strings and array-like objects

Strings have their own slice() with the same rules:

"hello world".slice(0, 5);   // "hello"
"hello".slice(-3);           // "llo"

To turn arguments or a NodeList into an array, Array.from() is the modern choice. Older code uses Array.prototype.slice.call(list), which does the same.

Use AI to work with slice()

An assistant like ChatGPT, Claude or GitHub Copilot can write the right indexes and explain an unexpected result. These three prompts are ready to copy.

1. Get part of an array

In JavaScript I have this array: [paste a short example].
I need [the first 3 / the last 2 / from the 2nd to the 5th] items without changing it.
Show me the code with slice() and explain the numbers.

2. Explain a result

This JavaScript code: [paste your code]
returns [what you see] and I expected [what you expected].
Explain why and how to fix it.

3. Paginate data

I have an array of [number] items in JavaScript and I want to show [number] per page.
Write a function that returns the items of a given page and the total number of pages.

Test the answer with the first page, the last page and a page that doesn't exist.

Common problems with slice()

Related guides

• JavaScript array fill()
• How to clear an array in JavaScript
• How to clone an array in JavaScript
• How to get the last element of an array in JavaScript
• How to flatten an array in JavaScript
• JavaScript array intersection