IsArray

Since 1.0.0

Check if a type is an array.

Signature

type IsArray<T> = T extends readonly unknown[]
  ? T extends readonly [...unknown[]]
    ? true
    : false
  : false

Parameters

Parameter	Description
T	The type to check

Returns

Returns true if T is an array type, false otherwise.

Examples

Basic Usage

import type { IsArray } from 'uni-types'

type Check1 = IsArray<string[]> // true
type Check2 = IsArray<number[]> // true
type Check3 = IsArray<readonly string[]> // true

Non-Array Types

type Check4 = IsArray<string> // false
type Check5 = IsArray<number> // false
type Check6 = IsArray<{ length: number }> // false
type Check7 = IsArray<{ [key: string]: any }> // false

With Tuples

type Check8 = IsArray<[string, number]> // true (tuples are arrays)

Usage in Conditional Types

import type { IsArray } from 'uni-types'

type ArrayElement<T> = IsArray<T> extends true ? T[number] : never

type Elem = ArrayElement<string[]> // string
type NotArray = ArrayElement<string> // never

Related

• IsTuple - Check if type is a tuple
• ArrayElement - Get array element type