code: function LRU(size) {
  		if (typeof size === 'undefined') {
  			this._max = -1;
  		} else {
  			this._max = size;
  		}
  		this._start = this._end = null;
  		this._size = 0;
  		this._cache = Object.create(null);
  	}
docs: @description Creates a new LRU cache with the given maximum size. If no size is given
  an unbounded cache is created.
  
  @constructor
  @param {Number} size The maximum size of the LRU or -1 for an unbounded cache
  @returns {javascript.LRU} A new LRU instance
  @since 8.0