internal/getView.js

define([], function() {

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

  /**
   * Gets the view, applying any `transforms` to the `start` and `end` positions.
   *
   * @private
   * @param {number} start The start of the view.
   * @param {number} end The end of the view.
   * @param {Array} [transforms] The transformations to apply to the view.
   * @returns {Object} Returns an object containing the `start` and `end`
   *  positions of the view.
   */
  function getView(start, end, transforms) {
    var index = -1,
        length = transforms ? transforms.length : 0;

    while (++index < length) {
      var data = transforms[index],
          size = data.size;

      switch (data.type) {
        case 'drop':      start += size; break;
        case 'dropRight': end -= size; break;
        case 'take':      end = nativeMin(end, start + size); break;
        case 'takeRight': start = nativeMax(start, end - size); break;
      }
    }
    return { 'start': start, 'end': end };
  }

  return getView;
});