import type { Arg0, Fn } from "../HKT";
import type { AssertNum } from "../helpers";

/**
 * Get the absolute value of a number.
 *
 * Sig: `(n: number) => number`
 */
export type Abs<N extends number> = AssertNum<
  number extends N ? number
  : `${N}` extends `-${infer T extends number}` ? T
  : N
>;

/**
 * [Fn] Get the absolute value of a number.
 *
 * Sig: `(n: number) => number`
 */
export default interface AbsFn extends Fn<[number], number> {
  def: () => Abs<Arg0<this>>;
}