isArray

Problem

You need to check whether a value is an array, optionally narrowing the item type with a guard.

Solution

Use isArray(value, itemGuard?) to guard array type. Without itemGuard it checks Array.isArray; with one it also narrows the element type.

import { isArray, isString } from '@vielzeug/arsenal';

isArray([1, 2, 3]); // true
isArray('not an array'); // false

if (isArray(value, isString)) {
  value; // string[]
}

Related

• isPlainObject
• isEmpty