add Events.purge method,

- which all event method from the plot object

Author: etpinard

src/lib/events.js

@@ -114,7 +114,19 @@ var Events = {
          */
         return jQueryHandlerValue !== undefined ? jQueryHandlerValue :
             nodeEventHandlerValue;
+    },
+
+    purge: function(plotObj) {
+        delete plotObj._ev;
+        delete plotObj.on;
+        delete plotObj.once;
+        delete plotObj.removeListener;
+        delete plotObj.removeAllListeners;
+        delete plotObj.emit;
+
+        return plotObj;
     }
+
 };
 
 module.exports = Events;

src/plot_api/plot_api.js

@@ -2412,6 +2412,9 @@ Plotly.purge = function purge(gd) {
     // purge properties
     Plots.purge(gd);
 
+    // purge event emitter methods
+    Events.purge(gd);
+
     // remove plot container
     if(fullLayout._container) fullLayout._container.remove();
 

test/jasmine/tests/events_test.js

@@ -181,8 +181,15 @@ describe('Events', function() {
             expect(eventBaton).toBe(3);
             expect(result).toBe('pong');
         });
+    });
 
+    describe('purge', function() {
+        it('should remove all method from the plotObj', function() {
+            Events.init(plotObj);
+            Events.purge(plotObj);
 
+            expect(plotObj).toEqual({});
+        });
     });
 
 });