ts-toolbelt
Version:
TypeScript's largest utility library
26 lines (25 loc) • 1.05 kB
TypeScript
import { Key } from './_Internal';
import { AtLeast as OAtLeast } from '../Object/AtLeast';
import { ObjectOf } from './ObjectOf';
import { _ListOf } from '../Object/ListOf';
import { List } from './List';
import { Keys } from '../Any/Keys';
/**
* Make that at least one of the keys `K` are required in `L` at a time.
* @param L to make required
* @param K (?=`keyof L`) to choose fields
* @returns [[List]] [[Union]]
* @example
* ```ts
* import {L} from 'ts-toolbelt'
*
* type test0 = L.AtLeast<[1, 2, 3], 0> // [1, 2 | undefined, 3 | undefined]
* type test1 = L.AtLeast<[1, 2, 3], 0 | 1> // [1, 2 | undefined, 3 | undefined] | [1 | undefined, 2, 3 | undefined]
* type test2 = L.AtLeast<[1, 2, 3]>
* // | [1, 2, 3]
* // | [1, 2 | undefined, 3 | undefined]
* // | [1 | undefined, 2, 3 | undefined]
* // | [1 | undefined, 2 | undefined, 3]
* ```
*/
export declare type AtLeast<L extends List, K extends Key = Keys<L>> = OAtLeast<ObjectOf<L>, `${K & number}` | K> extends infer U ? U extends unknown ? _ListOf<U & {}> : never : never;