isArray
function isArray<T>(value: unknown): value is T[];
Array.isArray is the whole test, so an array from another frame counts and an array-like object — arguments, a NodeList, { length: 0 } — does not.
isX and nonX answer a question and never interrupt control flow; requireX and requireNonX hand the value back or throw. The scheme is explained in Validation conventions.
Parameters
Parameter | Type | Description |
|---|---|---|
|
| The value to check. |
Returns
boolean — true when the value is an array; otherwise false.
In TypeScript the guard narrows value to T[] inside the branch.
Examples
What passes and what does not
isArray([]); // => true
isArray([1, 2, 3]); // => true
isArray("abc"); // => false
isArray({ length: 0 }); // => false
isArray(null); // => false
See also
Source
23 September 2026
This documentation was generated with AI (Claude) from the library's source code.