JavaScript · Function

some

Array.prototype.some() tests whether at least one array element satisfies a callback. It returns true on the first truthy result and otherwise returns false.

How it works

Call some() with a callback that tests each array element. It returns true as soon as the callback produces a truthy result; if every tested element produces a falsy result, it returns false.

Syntax

some(callbackFn)
some(callbackFn, thisArg)

Parameters

Name	Type	Description
`callbackFn`	`function`	A function called for each visited element. It should return a truthy value when the element passes the test and a falsy value otherwise; it receives the element, index, and array.
`thisArg`	`any`	Optional value used as `this` when invoking `callbackFn`.

Returns

A boolean: true when the callback returns a truthy value for at least one visited element; otherwise false.

Key points

Use some() to ask whether at least one array element passes a predicate.
The method short-circuits on the first successful test, avoiding unnecessary later callback calls.
A complete scan with no truthy callback result produces false.
The callback's first argument is the element currently being examined.
The callback's second argument is the current element's numeric index.
The callback's third argument is the array on which some() was invoked.
The method can operate on suitable array-like values, not only actual Array instances.

Common mistakes

The callback does not run for holes in a sparse array, so missing indexes are skipped rather than tested.

Example: Check whether any array element passes a test

const numbers = [1, 3, 4, 7];
const hasEven = numbers.some((number) => number % 2 === 0);

console.log(hasEven); // true

The callback tests each number, and iteration stops when it finds 4.

When to use it

Existence checks

Validate input before continuing when any item meets a rule.

Conditional membership

Detect whether a collection contains an item with a particular property or state.

Efficient short-circuiting

Stop predicate evaluation as soon as a matching element is found.

Interview questions

QWhat does Array.prototype.some() return and when does it stop?

some() returns a boolean indicating whether at least one array element makes the callback return a truthy value. It short-circuits and returns true immediately on the first match; otherwise it returns false.

Follow-up: What happens for an empty array? It returns false, because no element can satisfy the predicate.

QWhat arguments can the callback receive?

The callback receives the current element, its index, and the array being traversed. An optional thisArg supplies the callback's this value.

Follow-up: Does an arrow callback use thisArg? No. Arrow functions capture lexical this, so they do not rebind it from thisArg.

QHow does some() handle sparse arrays and array-like objects?

some() invokes the callback only for indexes that have assigned values, so sparse-array holes are skipped. It is also generic: it only requires a length property and integer-keyed properties on its this value.

Follow-up: Can it be used on an array-like object? Yes, when called generically, provided the object has the required length and integer-keyed properties.

Array.prototype.every()
Array.prototype.find()
Array.prototype.includes()
Array.prototype.filter()

Source: Array.prototype.some(). Checked 2026-10-15.