lodash/_createRecurry.js

var isLaziable = require('./_isLaziable'),
    setData = require('./_setData'),
    setWrapToString = require('./_setWrapToString');

/** Used to compose bitmasks for function metadata. */
var WRAP_BIND_FLAG = 1,
    WRAP_BIND_KEY_FLAG = 2,
    WRAP_CURRY_BOUND_FLAG = 4,
    WRAP_CURRY_FLAG = 8,
    WRAP_PARTIAL_FLAG = 32,
    WRAP_PARTIAL_RIGHT_FLAG = 64;

/**
 * Creates a function that wraps `func` to continue currying.
 *
 * @private
 * @param {Function} func The function to wrap.
 * @param {number} bitmask The bitmask flags. See `createWrap` for more details.
 * @param {Function} wrapFunc The function to create the `func` wrapper.
 * @param {*} placeholder The placeholder value.
 * @param {*} [thisArg] The `this` binding of `func`.
 * @param {Array} [partials] The arguments to prepend to those provided to
 *  the new function.
 * @param {Array} [holders] The `partials` placeholder indexes.
 * @param {Array} [argPos] The argument positions of the new function.
 * @param {number} [ary] The arity cap of `func`.
 * @param {number} [arity] The arity of `func`.
 * @returns {Function} Returns the new wrapped function.
 */
function createRecurry(func, bitmask, wrapFunc, placeholder, thisArg, partials, holders, argPos, ary, arity) {
  var isCurry = bitmask & WRAP_CURRY_FLAG,
      newHolders = isCurry ? holders : undefined,
      newHoldersRight = isCurry ? undefined : holders,
      newPartials = isCurry ? partials : undefined,
      newPartialsRight = isCurry ? undefined : partials;

  bitmask |= (isCurry ? WRAP_PARTIAL_FLAG : WRAP_PARTIAL_RIGHT_FLAG);
  bitmask &= ~(isCurry ? WRAP_PARTIAL_RIGHT_FLAG : WRAP_PARTIAL_FLAG);

  if (!(bitmask & WRAP_CURRY_BOUND_FLAG)) {
    bitmask &= ~(WRAP_BIND_FLAG | WRAP_BIND_KEY_FLAG);
  }
  var newData = [
    func, bitmask, thisArg, newPartials, newHolders, newPartialsRight,
    newHoldersRight, argPos, ary, arity
  ];

  var result = wrapFunc.apply(undefined, newData);
  if (isLaziable(func)) {
    setData(result, newData);
  }
  result.placeholder = placeholder;
  return setWrapToString(result, func, bitmask);
}

module.exports = createRecurry;