type-plus
Version:
Provides additional types for TypeScript.
28 lines • 1.39 kB
TypeScript
import type { DigitArray } from '../math/numeric_struct.js';
import type { IsInteger } from '../numeric/integer.js';
import type { IsPositive } from '../numeric/positive.js';
/**
* Creates `Tuple<T>` with `L` number of elements.
* @note Other cool implementations by @lazytype, @jcalz:
* @see https://github.com/microsoft/TypeScript/issues/26223#issuecomment-674514787
* @see https://github.com/microsoft/TypeScript/issues/47874#issuecomment-1039157322
*/
export type CreateTuple<L extends number, T = unknown, Fail = never> = number extends L ? T[] : IsPositive<L> extends true ? IsInteger<L> extends true ? ToTuple<[], DigitArray.FromString<`${L}`>, T> : Fail : Fail;
export type ToTuple<R extends any[], S extends number[], X = any> = S['length'] extends 0 ? R : S['length'] extends 1 ? [...R, ...DigitToTuple<X>[S[0]]] : S extends [any, ...infer T] ? T extends any[] ? ToTuple<Multi10<[...R, ...DigitToTuple<X>[S[0]]]>, T> : never : never;
type DigitToTuple<T = 1> = {
[k in number]: any[];
} & {
0: [];
1: [T];
2: [T, T];
3: [T, T, T];
4: [T, T, T, T];
5: [T, T, T, T, T];
6: [T, T, T, T, T, T];
7: [T, T, T, T, T, T, T];
8: [T, T, T, T, T, T, T, T];
9: [T, T, T, T, T, T, T, T, T];
};
type Multi10<C extends any[]> = [...C, ...C, ...C, ...C, ...C, ...C, ...C, ...C, ...C, ...C];
export {};
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