import type {BuiltIns, HasMultipleCallSignatures} from './internal'; /** Convert `object`s, `Map`s, `Set`s, and `Array`s and all of their keys/elements into immutable structures recursively. This is useful when a deeply nested structure needs to be exposed as completely immutable, for example, an imported JSON module or when receiving an API response that is passed around. Please upvote [this issue](https://github.com/microsoft/TypeScript/issues/13923) if you want to have this type as a built-in in TypeScript. @example ``` // data.json { "foo": ["bar"] } // main.ts import type {ReadonlyDeep} from 'type-fest'; import dataJson = require('./data.json'); const data: ReadonlyDeep<typeof dataJson> = dataJson; export default data; // test.ts import data from './main'; data.foo.push('bar'); //=> error TS2339: Property 'push' does not exist on type 'readonly string[]' ``` Note that types containing overloaded functions are not made deeply readonly due to a [TypeScript limitation](https://github.com/microsoft/TypeScript/issues/29732). @category Object @category Array @category Set @category Map */ export type ReadonlyDeep<T> = T extends BuiltIns ? T : T extends new (...arguments_: any[]) => unknown ? T // Skip class constructors : T extends (...arguments_: any[]) => unknown ? {} extends ReadonlyObjectDeep<T> ? T : HasMultipleCallSignatures<T> extends true ? T : ((...arguments_: Parameters<T>) => ReturnType<T>) & ReadonlyObjectDeep<T> : T extends Readonly<ReadonlyMap<infer KeyType, infer ValueType>> ? ReadonlyMapDeep<KeyType, ValueType> : T extends Readonly<ReadonlySet<infer ItemType>> ? ReadonlySetDeep<ItemType> : // Identify tuples to avoid converting them to arrays inadvertently; special case `readonly [...never[]]`, as it emerges undesirably from recursive invocations of ReadonlyDeep below. T extends readonly [] | readonly [...never[]] ? readonly [] : T extends readonly [infer U, ...infer V] ? readonly [ReadonlyDeep<U>, ...ReadonlyDeep<V>] : T extends readonly [...infer U, infer V] ? readonly [...ReadonlyDeep<U>, ReadonlyDeep<V>] : T extends ReadonlyArray<infer ItemType> ? ReadonlyArray<ReadonlyDeep<ItemType>> : T extends object ? ReadonlyObjectDeep<T> : unknown; /** Same as `ReadonlyDeep`, but accepts only `ReadonlyMap`s as inputs. Internal helper for `ReadonlyDeep`. */ type ReadonlyMapDeep<KeyType, ValueType> = {} & Readonly<ReadonlyMap<ReadonlyDeep<KeyType>, ReadonlyDeep<ValueType>>>; /** Same as `ReadonlyDeep`, but accepts only `ReadonlySet`s as inputs. Internal helper for `ReadonlyDeep`. */ type ReadonlySetDeep<ItemType> = {} & Readonly<ReadonlySet<ReadonlyDeep<ItemType>>>; /** Same as `ReadonlyDeep`, but accepts only `object`s as inputs. Internal helper for `ReadonlyDeep`. */ type ReadonlyObjectDeep<ObjectType extends object> = { readonly [KeyType in keyof ObjectType]: ReadonlyDeep<ObjectType[KeyType]> };