Ts Playground 35 Upd May 2026
type DeepReadonly<T> = { readonly [P in keyof T]: DeepReadonly<T[P]>; }; interface ApiResponse { user: { name: string; settings: { theme: string } }; }
Happy typing. — The TypeScript Playground Team ts playground 35
Date: April 14, 2026 Author: TypeScript Team / Community Spotlight type DeepReadonly<T> = { readonly [P in keyof
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let data: DeepReadonly<ApiResponse>; data.user.settings.theme = "dark"; // Error: Cannot assign to 'theme' settings: { theme: string } }
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