ramda.curry/curry.js

R.curry exported as a module

//  Ramda v0.26.1
//  https://github.com/ramda/ramda
//  (c) 2013-2019 Scott Sauyet, Michael Hurley, and David Chambers
//  Ramda may be freely distributed under the MIT license.

(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
  typeof define === 'function' && define.amd ? define(['exports'], factory) :
  (factory((global.R = {})));
}(this, (function (exports) { 'use strict';

  function _isPlaceholder(a) {
    return a != null &&
           typeof a === 'object' &&
           a['@@functional/placeholder'] === true;
  }

  /**
   * Optimized internal one-arity curry function.
   *
   * @private
   * @category Function
   * @param {Function} fn The function to curry.
   * @return {Function} The curried function.
   */
  function _curry1(fn) {
    return function f1(a) {
      if (arguments.length === 0 || _isPlaceholder(a)) {
        return f1;
      } else {
        return fn.apply(this, arguments);
      }
    };
  }

  function _arity(n, fn) {
    /* eslint-disable no-unused-vars */
    switch (n) {
      case 0: return function() { return fn.apply(this, arguments); };
      case 1: return function(a0) { return fn.apply(this, arguments); };
      case 2: return function(a0, a1) { return fn.apply(this, arguments); };
      case 3: return function(a0, a1, a2) { return fn.apply(this, arguments); };
      case 4: return function(a0, a1, a2, a3) { return fn.apply(this, arguments); };
      case 5: return function(a0, a1, a2, a3, a4) { return fn.apply(this, arguments); };
      case 6: return function(a0, a1, a2, a3, a4, a5) { return fn.apply(this, arguments); };
      case 7: return function(a0, a1, a2, a3, a4, a5, a6) { return fn.apply(this, arguments); };
      case 8: return function(a0, a1, a2, a3, a4, a5, a6, a7) { return fn.apply(this, arguments); };
      case 9: return function(a0, a1, a2, a3, a4, a5, a6, a7, a8) { return fn.apply(this, arguments); };
      case 10: return function(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9) { return fn.apply(this, arguments); };
      default: throw new Error('First argument to _arity must be a non-negative integer no greater than ten');
    }
  }

  /**
   * Optimized internal two-arity curry function.
   *
   * @private
   * @category Function
   * @param {Function} fn The function to curry.
   * @return {Function} The curried function.
   */
  function _curry2(fn) {
    return function f2(a, b) {
      switch (arguments.length) {
        case 0:
          return f2;
        case 1:
          return _isPlaceholder(a)
            ? f2
            : _curry1(function(_b) { return fn(a, _b); });
        default:
          return _isPlaceholder(a) && _isPlaceholder(b)
            ? f2
            : _isPlaceholder(a)
              ? _curry1(function(_a) { return fn(_a, b); })
              : _isPlaceholder(b)
                ? _curry1(function(_b) { return fn(a, _b); })
                : fn(a, b);
      }
    };
  }

  /**
   * Internal curryN function.
   *
   * @private
   * @category Function
   * @param {Number} length The arity of the curried function.
   * @param {Array} received An array of arguments received thus far.
   * @param {Function} fn The function to curry.
   * @return {Function} The curried function.
   */
  function _curryN(length, received, fn) {
    return function() {
      var combined = [];
      var argsIdx = 0;
      var left = length;
      var combinedIdx = 0;
      while (combinedIdx < received.length || argsIdx < arguments.length) {
        var result;
        if (combinedIdx < received.length &&
            (!_isPlaceholder(received[combinedIdx]) ||
             argsIdx >= arguments.length)) {
          result = received[combinedIdx];
        } else {
          result = arguments[argsIdx];
          argsIdx += 1;
        }
        combined[combinedIdx] = result;
        if (!_isPlaceholder(result)) {
          left -= 1;
        }
        combinedIdx += 1;
      }
      return left <= 0
        ? fn.apply(this, combined)
        : _arity(left, _curryN(length, combined, fn));
    };
  }

  /**
   * Returns a curried equivalent of the provided function, with the specified
   * arity. The curried function has two unusual capabilities. First, its
   * arguments needn't be provided one at a time. If `g` is `R.curryN(3, f)`, the
   * following are equivalent:
   *
   *   - `g(1)(2)(3)`
   *   - `g(1)(2, 3)`
   *   - `g(1, 2)(3)`
   *   - `g(1, 2, 3)`
   *
   * Secondly, the special placeholder value [`R.__`](#__) may be used to specify
   * "gaps", allowing partial application of any combination of arguments,
   * regardless of their positions. If `g` is as above and `_` is [`R.__`](#__),
   * the following are equivalent:
   *
   *   - `g(1, 2, 3)`
   *   - `g(_, 2, 3)(1)`
   *   - `g(_, _, 3)(1)(2)`
   *   - `g(_, _, 3)(1, 2)`
   *   - `g(_, 2)(1)(3)`
   *   - `g(_, 2)(1, 3)`
   *   - `g(_, 2)(_, 3)(1)`
   *
   * @func
   * @memberOf R
   * @since v0.5.0
   * @category Function
   * @sig Number -> (* -> a) -> (* -> a)
   * @param {Number} length The arity for the returned function.
   * @param {Function} fn The function to curry.
   * @return {Function} A new, curried function.
   * @see R.curry
   * @example
   *
   *      const sumArgs = (...args) => R.sum(args);
   *
   *      const curriedAddFourNumbers = R.curryN(4, sumArgs);
   *      const f = curriedAddFourNumbers(1, 2);
   *      const g = f(3);
   *      g(4); //=> 10
   */
  var curryN = _curry2(function curryN(length, fn) {
    if (length === 1) {
      return _curry1(fn);
    }
    return _arity(length, _curryN(length, [], fn));
  });

  /**
   * Returns a curried equivalent of the provided function. The curried function
   * has two unusual capabilities. First, its arguments needn't be provided one
   * at a time. If `f` is a ternary function and `g` is `R.curry(f)`, the
   * following are equivalent:
   *
   *   - `g(1)(2)(3)`
   *   - `g(1)(2, 3)`
   *   - `g(1, 2)(3)`
   *   - `g(1, 2, 3)`
   *
   * Secondly, the special placeholder value [`R.__`](#__) may be used to specify
   * "gaps", allowing partial application of any combination of arguments,
   * regardless of their positions. If `g` is as above and `_` is [`R.__`](#__),
   * the following are equivalent:
   *
   *   - `g(1, 2, 3)`
   *   - `g(_, 2, 3)(1)`
   *   - `g(_, _, 3)(1)(2)`
   *   - `g(_, _, 3)(1, 2)`
   *   - `g(_, 2)(1)(3)`
   *   - `g(_, 2)(1, 3)`
   *   - `g(_, 2)(_, 3)(1)`
   *
   * @func
   * @memberOf R
   * @since v0.1.0
   * @category Function
   * @sig (* -> a) -> (* -> a)
   * @param {Function} fn The function to curry.
   * @return {Function} A new, curried function.
   * @see R.curryN, R.partial
   * @example
   *
   *      const addFourNumbers = (a, b, c, d) => a + b + c + d;
   *
   *      const curriedAddFourNumbers = R.curry(addFourNumbers);
   *      const f = curriedAddFourNumbers(1, 2);
   *      const g = f(3);
   *      g(4); //=> 10
   */
  var curry = _curry1(function curry(fn) {
    return curryN(fn.length, fn);
  });

  exports.curry = curry;

  Object.defineProperty(exports, '__esModule', { value: true });

})));