ObjectReadonly.md

typelab / utils / ObjectReadonly

type ObjectReadonly<T, K> = IsObjectLiteral<T> extends true ? Detailed<{ readonly [Key in K]: T[K] } & { [Key in keyof T as Key extends K ? never : Key]: T[Key] }> : never;

Extended TypeScript `Readonly` to enforce specific properties as readonly.

Type Parameters

Type Parameter	Description
T	The original object type.
K extends keyof T	The keys of T that should be readonly.

Returns

A type with the specified keys of T set as readonly.

Example

type Obj = { a: string; b: string };

// { readonly a: string; b: string }
type ReadonlyObj = ObjectReadonly<Obj, 'a'>;