index.js #1

/**
 * Lo-Dash 2.3.0 (Custom Build) <http://lodash.com/>
 * Build: `lodash modularize modern exports="npm" -o ./npm/`
 * Copyright 2012-2013 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.5.2 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <http://lodash.com/license>
 */
var baseBind = require('lodash._basebind'),
    baseCreateWrapper = require('lodash._basecreatewrapper'),
    isFunction = require('lodash.isfunction');

/**
 * Used for `Array` method references.
 *
 * Normally `Array.prototype` would suffice, however, using an array literal
 * avoids issues in Narwhal.
 */
var arrayRef = [];

/** Native method shortcuts */
var push = arrayRef.push;

/**
 * Creates a function that, when called, either curries or invokes `func`
 * with an optional `this` binding and partially applied arguments.
 *
 * @private
 * @param {Function|string} func The function or method name to reference.
 * @param {number} bitmask The bitmask of method flags to compose.
 *  The bitmask may be composed of the following flags:
 *  1 - `_.bind`
 *  2 - `_.bindKey`
 *  4 - `_.curry`
 *  8 - `_.curry` (bound)
 *  16 - `_.partial`
 *  32 - `_.partialRight`
 * @param {Array} [partialArgs] An array of arguments to prepend to those
 *  provided to the new function.
 * @param {Array} [partialRightArgs] An array of arguments to append to those
 *  provided to the new function.
 * @param {*} [thisArg] The `this` binding of `func`.
 * @param {number} [arity] The arity of `func`.
 * @returns {Function} Returns the new function.
 */
function createWrapper(func, bitmask, partialArgs, partialRightArgs, thisArg, arity) {
  var isBind = bitmask & 1,
      isBindKey = bitmask & 2,
      isCurry = bitmask & 4,
      isCurryBound = bitmask & 8,
      isPartial = bitmask & 16,
      isPartialRight = bitmask & 32;

  if (!isBindKey && !isFunction(func)) {
    throw new TypeError;
  }
  if (isPartial && !partialArgs.length) {
    bitmask &= ~16;
    isPartial = partialArgs = false;
  }
  if (isPartialRight && !partialRightArgs.length) {
    bitmask &= ~32;
    isPartialRight = partialRightArgs = false;
  }
  var bindData = func && func.__bindData__;
  if (bindData && bindData !== true) {
    bindData = bindData.slice();

    // set `thisBinding` is not previously bound
    if (isBind && !(bindData[1] & 1)) {
      bindData[4] = thisArg;
    }
    // set if previously bound but not currently (subsequent curried functions)
    if (!isBind && bindData[1] & 1) {
      bitmask |= 8;
    }
    // set curried arity if not yet set
    if (isCurry && !(bindData[1] & 4)) {
      bindData[5] = arity;
    }
    // append partial left arguments
    if (isPartial) {
      push.apply(bindData[2] || (bindData[2] = []), partialArgs);
    }
    // append partial right arguments
    if (isPartialRight) {
      push.apply(bindData[3] || (bindData[3] = []), partialRightArgs);
    }
    // merge flags
    bindData[1] |= bitmask;
    return createWrapper.apply(null, bindData);
  }
  // fast path for `_.bind`
  var creater = (bitmask == 1 || bitmask === 17) ? baseBind : baseCreateWrapper;
  return creater([func, bitmask, partialArgs, partialRightArgs, thisArg, arity]);
}

module.exports = createWrapper;