until.ts

// Copyright (c) 2020 Jozty. All rights reserved. MIT license.

import curryN from './utils/curry_n.ts';
import type {
  FuncArr1,
  InferPrimitive,
  PH,
  Predicate1,
} from './utils/types.ts';

// @types
type Until_1<T> = (pred: Predicate1<T>) => T;

type Until_2<T> = (fn: FuncArr1<T, T>) => T;

type Until_3<T> = (init: T) => T;

type Until_2_3<T> =
  & ((fn: FuncArr1<T, T>) => Until_3<T>)
  & (<T>(fn: PH, init: T) => Until_2<T>)
  & ((fn: FuncArr1<T, T>, init: T) => T);

type Until_1_3<T> =
  & ((pred: Predicate1<T>) => Until_3<T>)
  & (<T>(pred: PH, init: T) => Until_1<T>)
  & ((pred: Predicate1<T>, init: T) => T);

type Until_1_2<T> =
  & ((pred: Predicate1<T>) => Until_2<T>)
  & ((pred: PH, fn: FuncArr1<T, T>) => Until_1<T>)
  & ((pred: Predicate1<T>, fn: FuncArr1<T, T>) => T);

type Until =
  & (<T>(pred: Predicate1<T>) => Until_2_3<T>)
  & (<T>(pred: PH, fn: FuncArr1<T, T>) => Until_1_3<T>)
  & (<T>(pred: PH, fn: PH, init: T) => Until_1_2<InferPrimitive<T>>)
  & (<T>(pred: Predicate1<T>, fn: FuncArr1<T, T>) => Until_3<T>)
  & (<T>(pred: Predicate1<T>, fn: PH, init: T) => Until_2<InferPrimitive<T>>)
  & (<T>(pred: PH, fn: FuncArr1<T, T>, init: T) => Until_1<T>)
  & (<T>(pred: Predicate1<T>, fn: FuncArr1<T, T>, init: T) => T);

function _until<T>(pred: Predicate1<T>, fn: FuncArr1<T, T>, init: T) {
  let val = init;
  while (!pred(val)) {
    val = fn(val);
  }
  return val;
}

/**
 * Takes a predicate, a transformation function, and an initial value,
 * and returns a value of the same type as the initial value.
 */
export const until = curryN(3, _until) as Until;