import type { Args, Fn } from "../HKT";
import type { AssertStr } from "../helpers";

/**
 * Append a string (the 1st argument) to another string (the 2nd argument).
 *
 * Sig: `(ext: string, s: string) => string`
 */
export type Append<Ext extends string, S extends string> = AssertStr<`${S}${Ext}`>;

/**
 * [Fn] Append a string (the 1st argument) to another string (the 2nd argument).
 *
 * Sig: `(ext: string, s: string) => string`
 */
export default interface AppendFn extends Fn<[string, string], string> {
  def: ([ext, s]: Args<this>) => Append<typeof ext, typeof s>;
}