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✏️ Editing: createHybridWrapper.js

var arrayCopy = require('./arrayCopy'),
    composeArgs = require('./composeArgs'),
    composeArgsRight = require('./composeArgsRight'),
    createCtorWrapper = require('./createCtorWrapper'),
    isLaziable = require('./isLaziable'),
    reorder = require('./reorder'),
    replaceHolders = require('./replaceHolders'),
    setData = require('./setData');

/** Used to compose bitmasks for wrapper metadata. */
var BIND_FLAG = 1,
    BIND_KEY_FLAG = 2,
    CURRY_BOUND_FLAG = 4,
    CURRY_FLAG = 8,
    CURRY_RIGHT_FLAG = 16,
    PARTIAL_FLAG = 32,
    PARTIAL_RIGHT_FLAG = 64,
    ARY_FLAG = 128;

/* Native method references for those with the same name as other `lodash` methods. */
var nativeMax = Math.max;

/**
 * Creates a function that wraps `func` and invokes it with optional `this`
 * binding of, partial application, and currying.
 *
 * @private
 * @param {Function|string} func The function or method name to reference.
 * @param {number} bitmask The bitmask of flags. See `createWrapper` for more details.
 * @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} [partialsRight] The arguments to append to those provided to the new function.
 * @param {Array} [holdersRight] The `partialsRight` 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 createHybridWrapper(func, bitmask, thisArg, partials, holders, partialsRight, holdersRight, argPos, ary, arity) {
  var isAry = bitmask & ARY_FLAG,
      isBind = bitmask & BIND_FLAG,
      isBindKey = bitmask & BIND_KEY_FLAG,
      isCurry = bitmask & CURRY_FLAG,
      isCurryBound = bitmask & CURRY_BOUND_FLAG,
      isCurryRight = bitmask & CURRY_RIGHT_FLAG,
      Ctor = isBindKey ? undefined : createCtorWrapper(func);

function wrapper() {
    // Avoid `arguments` object use disqualifying optimizations by
    // converting it to an array before providing it to other functions.
    var length = arguments.length,
        index = length,
        args = Array(length);

while (index--) {
      args[index] = arguments[index];
    }
    if (partials) {
      args = composeArgs(args, partials, holders);
    }
    if (partialsRight) {
      args = composeArgsRight(args, partialsRight, holdersRight);
    }
    if (isCurry || isCurryRight) {
      var placeholder = wrapper.placeholder,
          argsHolders = replaceHolders(args, placeholder);

length -= argsHolders.length;
      if (length < arity) {
        var newArgPos = argPos ? arrayCopy(argPos) : undefined,
            newArity = nativeMax(arity - length, 0),
            newsHolders = isCurry ? argsHolders : undefined,
            newHoldersRight = isCurry ? undefined : argsHolders,
            newPartials = isCurry ? args : undefined,
            newPartialsRight = isCurry ? undefined : args;

bitmask |= (isCurry ? PARTIAL_FLAG : PARTIAL_RIGHT_FLAG);
        bitmask &= ~(isCurry ? PARTIAL_RIGHT_FLAG : PARTIAL_FLAG);

if (!isCurryBound) {
          bitmask &= ~(BIND_FLAG | BIND_KEY_FLAG);
        }
        var newData = [func, bitmask, thisArg, newPartials, newsHolders, newPartialsRight, newHoldersRight, newArgPos, ary, newArity],
            result = createHybridWrapper.apply(undefined, newData);

if (isLaziable(func)) {
          setData(result, newData);
        }
        result.placeholder = placeholder;
        return result;
      }
    }
    var thisBinding = isBind ? thisArg : this,
        fn = isBindKey ? thisBinding[func] : func;

if (argPos) {
      args = reorder(args, argPos);
    }
    if (isAry && ary < args.length) {
      args.length = ary;
    }
    if (this && this !== global && this instanceof wrapper) {
      fn = Ctor || createCtorWrapper(func);
    }
    return fn.apply(thisBinding, args);
  }
  return wrapper;
}

module.exports = createHybridWrapper;

MR SKB