ramda-adjunct/lib/Y.js

Ramda Adjunct is the most popular and most comprehensive set of utilities for use with Ramda, providing a variety of useful, well tested functions with excellent documentation.

"use strict";

exports.__esModule = true;
exports["default"] = void 0;

var _ramda = require("ramda");

/**
 * Y-combinator
 *
 * The Y combinator is an interesting function which only works with functional languages,
 * showing how recursion can still be done even without any variable or function declarations,
 * only functions and parameters
 *
 * @func Y
 * @memberOf RA
 * @since {@link https://char0n.github.io/ramda-adjunct/2.3.0|v2.3.0}
 * @category Function
 * @sig (a, ... -> b -> b) -> (a, ... -> b)
 * @param {Function} le Recursive function maker
 * @return {Function}
 * @see {@link http://kestas.kuliukas.com/YCombinatorExplained/|Y combinator explained}
 * @example
 *
 * const makeFact = givenFact => (n) => {
 *   if (n < 2) { return 1 }
 *   return n * givenFact(n - 1);
 * };
 *
 * const factorial = RA.Y(makeFact);
 *
 * factorial(5); //=> 120
 */
var Y = (0, _ramda.curryN)(1, function (le) {
  return function (f) {
    return f(f);
  }(function (g) {
    return le(function (x) {
      return g(g)(x);
    });
  });
});
var _default = Y;
exports["default"] = _default;