blob: 0a7233077e286fc48efea245a2ea7d5981de0cc1 [file] [log] [blame]
import {Except} from './except';
/**
Create a type that makes the given keys required. The remaining keys are kept as is. The sister of the `SetOptional` type.
Use-case: You want to define a single model where the only thing that changes is whether or not some of the keys are required.
@example
```
import {SetRequired} from 'type-fest';
type Foo = {
a?: number;
b: string;
c?: boolean;
}
type SomeRequired = SetRequired<Foo, 'b' | 'c'>;
// type SomeRequired = {
// a?: number;
// b: string; // Was already required and still is.
// c: boolean; // Is now required.
// }
```
*/
export type SetRequired<BaseType, Keys extends keyof BaseType = keyof BaseType> =
// Pick just the keys that are not required from the base type.
Except<BaseType, Keys> &
// Pick the keys that should be required from the base type and make them required.
Required<Pick<BaseType, Keys>> extends
// If `InferredType` extends the previous, then for each key, use the inferred type key.
infer InferredType
? {[KeyType in keyof InferredType]: InferredType[KeyType]}
: never;