types-kit.isreadonlyarray.md

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IsReadonlyArray type

If T is a readonly array, return true, else return false.

Signature:

export type IsReadonlyArray<T extends readonly unknown[]> = T extends T
  ? Not<IsExtends<T, any[]>>
  : never

References: Not, IsExtends

Example

// Expect: true
type Foo = IsReadonlyArray<readonly [1, 2, 3]>