code: function (userOptions) {
  		this.options = merge(
  			this.defaultOptions,
  			this.isXAxis ? {} : this.defaultYAxisOptions,
  			[this.defaultTopAxisOptions, this.defaultRightAxisOptions,
  				this.defaultBottomAxisOptions, this.defaultLeftAxisOptions][this.side],
  			merge(
  				defaultOptions[this.isXAxis ? 'xAxis' : 'yAxis'], // if set in setOptions (#1053)
  				userOptions
  			)
  		);
  	}
docs: Merge and set options