code: function (providerName) {
  		if (providerName === 'ignored') {
  			return true;
  		}
  		// reduce the number of layers previewed for some providers
  		if (providerName.startsWith('HERE') || providerName.startsWith('OpenWeatherMap') || providerName.startsWith('MapBox')) {
  			var whitelist = [
  				// API threshold almost reached, disabling for now.
  				// 'HERE.normalDay',
  				'OpenWeatherMap.Clouds',
  				'OpenWeatherMap.Pressure',
  				'OpenWeatherMap.Wind'
  			];
  			return whitelist.indexOf(providerName) === -1;
  		}
  		return false;
  	}
docs: Ignore some providers in the preview