Skip to content
Permalink
Branch: master
Find file Copy path
Find file Copy path
1 contributor

Users who have contributed to this file

60 lines (47 sloc) 1.8 KB
import {Primitive} from './basic';
/**
Convert `object`s, `Map`s, `Set`s, and `Array`s and all of their properties/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 {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[]'
```
*/
export type ReadonlyDeep<T> = T extends Primitive | ((...arguments: any[]) => unknown)
? T
: T extends ReadonlyMap<infer KeyType, infer ValueType>
? ReadonlyMapDeep<KeyType, ValueType>
: T extends ReadonlySet<infer ItemType>
? ReadonlySetDeep<ItemType>
: T extends object
? ReadonlyObjectDeep<T>
: unknown;
/**
Same as `ReadonlyDeep`, but accepts only `ReadonlyMap`s as inputs. Internal helper for `ReadonlyDeep`.
*/
interface ReadonlyMapDeep<KeyType, ValueType>
extends ReadonlyMap<ReadonlyDeep<KeyType>, ReadonlyDeep<ValueType>> {}
/**
Same as `ReadonlyDeep`, but accepts only `ReadonlySet`s as inputs. Internal helper for `ReadonlyDeep`.
*/
interface ReadonlySetDeep<ItemType>
extends ReadonlySet<ReadonlyDeep<ItemType>> {}
/**
Same as `ReadonlyDeep`, but accepts only `object`s as inputs. Internal helper for `ReadonlyDeep`.
*/
type ReadonlyObjectDeep<ObjectType extends object> = {
readonly [PropertyType in keyof ObjectType]: ReadonlyDeep<ObjectType[PropertyType]>
};
You can’t perform that action at this time.