Define options

src/ol/source/imagewmssource.js

@@ -31,7 +31,7 @@ goog.require('ol.source.wms.ServerType');
  */
 ol.source.ImageWMS = function(opt_options) {
 
-  var options = goog.isDef(opt_options) ? opt_options : {};
+  var options = opt_options || {};
 
   goog.base(this, {
     attributions: options.attributions,

src/ol/source/mapquestsource.js

@@ -18,7 +18,7 @@ goog.require('ol.source.XYZ');
  */
 ol.source.MapQuest = function(opt_options) {
 
-  var options = goog.isDef(opt_options) ? opt_options : {};
+  var options = opt_options || {};
   goog.asserts.assert(options.layer in ol.source.MapQuestConfig,
       'known layer configured');
 

src/ol/source/osmsource.js

@@ -16,7 +16,7 @@ goog.require('ol.source.XYZ');
  */
 ol.source.OSM = function(opt_options) {
 
-  var options = goog.isDef(opt_options) ? opt_options : {};
+  var options = opt_options || {};
 
   var attributions;
   if (goog.isDef(options.attributions)) {

src/ol/source/tilearcgisrestsource.js

@@ -32,7 +32,7 @@ goog.require('ol.tilecoord');
  */
 ol.source.TileArcGISRest = function(opt_options) {
 
-  var options = goog.isDef(opt_options) ? opt_options : {};
+  var options = opt_options || {};
 
   var params = goog.isDef(options.params) ? options.params : {};
 

src/ol/source/tilewmssource.js

@@ -33,7 +33,7 @@ goog.require('ol.tilecoord');
  */
 ol.source.TileWMS = function(opt_options) {
 
-  var options = goog.isDef(opt_options) ? opt_options : {};
+  var options = opt_options || {};
 
   var params = goog.isDef(options.params) ? options.params : {};
 

src/ol/source/vectorsource.js

@@ -75,7 +75,7 @@ ol.source.VectorEventType = {
  */
 ol.source.Vector = function(opt_options) {
 
-  var options = goog.isDef(opt_options) ? opt_options : {};
+  var options = opt_options || {};
 
   goog.base(this, {
     attributions: options.attributions,

src/ol/source/zoomifysource.js

@@ -33,7 +33,7 @@ ol.source.ZoomifyTierSizeCalculation = {
  */
 ol.source.Zoomify = function(opt_options) {
 
-  var options = goog.isDef(opt_options) ? opt_options : {};
+  var options = opt_options || {};
 
   var size = options.size;
   var tierSizeCalculation = goog.isDef(options.tierSizeCalculation) ?