pipe.ts

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

import type { Any, Func, FuncArr1 } from './utils/types.ts';
import curryN from './utils/curry_n.ts';
import { reduce } from './reduce.ts';
import { getFunctionLength } from './utils/get.ts';

function _pipe(f: Func, g: Func) {
  return function (this: unknown, ...args: unknown[]): unknown {
    return g.call(this, f.apply(this, args));
  };
}

/**
 * Performs a left-to-right function composition.
 * The first function may have unknown number of arguments;
 * the remaining must have single argument.
 * **Note:** The returned function is automatically curried.
 */
export function pipe<A extends Any[], R, F2 extends FuncArr1<Any, Any>[]>(
  func: Func<A, R>,
  ...functions: F2
) {
  return curryN(
    getFunctionLength(func),
    reduce(_pipe, func as Func<Any[], Any>, functions),
  );
}