Type Alias DeepReadonly<T>

DeepReadonly: T extends Primitive
    ? T
    : T extends AnyFn
        ? T
        : T extends MutableMap<infer K, infer V>
            ? ReadonlyMap<DeepReadonly<K>, DeepReadonly<V>>
            : T extends ReadonlyMap<infer K, infer V>
                ? ReadonlyMap<DeepReadonly<K>, DeepReadonly<V>>
                : T extends MutableSet<infer V>
                    ? ReadonlySet<DeepReadonly<V>>
                    : T extends ReadonlySet<infer V>
                        ? ReadonlySet<DeepReadonly<V>>
                        : T extends Record<string, any>
                        | readonly unknown[]
                            ? { readonly [K in keyof T]: DeepReadonly<T[K]> }
                            : T

type Data = { a: number; b: { c: string[]; d: Map<number, boolean> } };
type ReadonlyData = DeepReadonly<Data>;
// Result: {
//   readonly a: number;
//   readonly b: {
//     readonly c: readonly string[];
//     readonly d: ReadonlyMap<number, boolean>;
//   };
// }
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