text: /**
   * Copyright 2014-2015, Facebook, Inc.
   * All rights reserved.
   *
   * This source code is licensed under the BSD-style license found in the
   * LICENSE file in the root directory of this source tree. An additional grant
   * of patent rights can be found in the PATENTS file in the same directory.
   *
   * @providesModule accumulateInto
   */
  
  'use strict';
  
  var invariant = require('fbjs/lib/invariant');
  
  /**
   *
   * Accumulates items that must not be null or undefined into the first one. This
   * is used to conserve memory by avoiding array allocations, and thus sacrifices
   * API cleanness. Since `current` can be null before being passed in and not
   * null after this function, make sure to assign it back to `current`:
   *
   * `a = accumulateInto(a, b);`
   *
   * This API should be sparingly used. Try `accumulate` for something cleaner.
   *
   * @return {*|array<*>} An accumulation of items.
   */
  
  function accumulateInto(current, next) {
    !(next != null) ? process.env.NODE_ENV !== 'production' ? invariant(false, 'accumulateInto(...): Accumulated items must not be null or undefined.') : invariant(false) : undefined;
    if (current == null) {
      return next;
    }
  
    // Both are not empty. Warning: Never call x.concat(y) when you are not
    // certain that x is an Array (x could be a string with concat method).
    var currentIsArray = Array.isArray(current);
    var nextIsArray = Array.isArray(next);
  
    if (currentIsArray && nextIsArray) {
      current.push.apply(current, next);
      return current;
    }
  
    if (currentIsArray) {
      current.push(next);
      return current;
    }
  
    if (nextIsArray) {
      // A bit too dangerous to mutate `next`.
      return [current].concat(next);
    }
  
    return [current, next];
  }
  
  module.exports = accumulateInto;