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

/**
 * Check if a number is negative.
 *
 * Sig: `(n: number) => boolean`
 */
export type IsNeg<N extends number> = AssertBool<`${N}` extends `-${string}` ? true : false>;

/**
 * [Fn] Check if a number is negative.
 *
 * Sig: `(n: number) => boolean`
 */
export default interface IsNegFn extends Fn<[number], boolean> {
  def: () => IsNeg<Arg0<this>>;
}