DeepReadonly

Since 1.0.0

Make all nested properties readonly recursively.

Signature

type DeepReadonly<T> = T extends BuiltIn
  ? T
  : T extends Map<infer K, infer V>
    ? ReadonlyMap<DeepReadonly<K>, DeepReadonly<V>>
    : T extends Set<infer V>
      ? ReadonlySet<DeepReadonly<V>>
      : T extends (infer E)[]
        ? readonly DeepReadonly<E>[]
        : T extends object
          ? { readonly [P in keyof T]: DeepReadonly<T[P]> }
          : T

Parameters

Parameter	Description
T	The target type

Description

Unlike TypeScript's built-in Readonly<T>, DeepReadonly recursively makes all nested properties readonly.

Examples

Basic Usage

import type { DeepReadonly } from 'uni-types'

interface Config {
  database: {
    host: string
    port: number
  }
}

type ReadonlyConfig = DeepReadonly<Config>
/*
{
  readonly database: {
    readonly host: string
    readonly port: number
  }
}
*/

With Arrays

interface Data {
  items: string[]
}

type ReadonlyData = DeepReadonly<Data>
// items becomes readonly string[]

Related

• DeepMutable - Make all nested properties mutable
• DeepPartial - Make all nested properties optional
• DeepRequired - Make all nested properties required