blob: b962b84eb6b4cdada8190d3e10704e98de051cee [file] [log] [blame]
import {Primitive} from './basic';
/**
Create a type from another type with all keys and nested keys set to optional.
Use-cases:
- Merging a default settings/config object with another object, the second object would be a deep partial of the default object.
- Mocking and testing complex entities, where populating an entire object with its keys would be redundant in terms of the mock or test.
@example
```
import {PartialDeep} from 'type-fest';
const settings: Settings = {
textEditor: {
fontSize: 14;
fontColor: '#000000';
fontWeight: 400;
}
autocomplete: false;
autosave: true;
};
const applySavedSettings = (savedSettings: PartialDeep<Settings>) => {
return {...settings, ...savedSettings};
}
settings = applySavedSettings({textEditor: {fontWeight: 500}});
```
*/
export type PartialDeep<T> = T extends Primitive
? Partial<T>
: T extends Map<infer KeyType, infer ValueType>
? PartialMapDeep<KeyType, ValueType>
: T extends Set<infer ItemType>
? PartialSetDeep<ItemType>
: T extends ReadonlyMap<infer KeyType, infer ValueType>
? PartialReadonlyMapDeep<KeyType, ValueType>
: T extends ReadonlySet<infer ItemType>
? PartialReadonlySetDeep<ItemType>
: T extends ((...arguments: any[]) => unknown)
? T | undefined
: T extends object
? PartialObjectDeep<T>
: unknown;
/**
Same as `PartialDeep`, but accepts only `Map`s and as inputs. Internal helper for `PartialDeep`.
*/
interface PartialMapDeep<KeyType, ValueType> extends Map<PartialDeep<KeyType>, PartialDeep<ValueType>> {}
/**
Same as `PartialDeep`, but accepts only `Set`s as inputs. Internal helper for `PartialDeep`.
*/
interface PartialSetDeep<T> extends Set<PartialDeep<T>> {}
/**
Same as `PartialDeep`, but accepts only `ReadonlyMap`s as inputs. Internal helper for `PartialDeep`.
*/
interface PartialReadonlyMapDeep<KeyType, ValueType> extends ReadonlyMap<PartialDeep<KeyType>, PartialDeep<ValueType>> {}
/**
Same as `PartialDeep`, but accepts only `ReadonlySet`s as inputs. Internal helper for `PartialDeep`.
*/
interface PartialReadonlySetDeep<T> extends ReadonlySet<PartialDeep<T>> {}
/**
Same as `PartialDeep`, but accepts only `object`s as inputs. Internal helper for `PartialDeep`.
*/
type PartialObjectDeep<ObjectType extends object> = {
[KeyType in keyof ObjectType]?: PartialDeep<ObjectType[KeyType]>
};