feat: Introduces connection event for custom properties. (#2493)

* feat: Introduces connection event for custom properties.

Used for shard and region values coming from the backend.

* squash: Update JitsiConnectionEvents.ts

* squash: Update JitsiConnectionEvents.ts

JitsiConnectionEvents.spec.ts

         CONNECTION_REDIRECTED,
         WRONG_STATE,
         DISPLAY_NAME_REQUIRED,
+        PROPERTIES_UPDATED,
         JitsiConnectionEvents,
         ...others
     } = exported;
         expect( CONNECTION_REDIRECTED ).toBe( 'connection.redirected' );
         expect( WRONG_STATE ).toBe( 'connection.wrongState' );
         expect( DISPLAY_NAME_REQUIRED ).toBe( 'connection.display_name_required' );
+        expect( PROPERTIES_UPDATED ).toBe( 'connection.propertiesUpdated' );
 
         expect( JitsiConnectionEvents ).toBeDefined();
 
         expect( JitsiConnectionEvents.CONNECTION_REDIRECTED ).toBe( 'connection.redirected' );
         expect( JitsiConnectionEvents.WRONG_STATE ).toBe( 'connection.wrongState' );
         expect( JitsiConnectionEvents.DISPLAY_NAME_REQUIRED ).toBe( 'connection.display_name_required' );
+        expect( JitsiConnectionEvents.PROPERTIES_UPDATED ).toBe( 'connection.propertiesUpdated' );
     } );
 
     it( "unknown members", () => {

JitsiConnectionEvents.ts

      * joining the room.
      * There are cases like lobby room where display name is required.
      */
-    DISPLAY_NAME_REQUIRED = 'connection.display_name_required'
+    DISPLAY_NAME_REQUIRED = 'connection.display_name_required',
+
+    /**
+     * Indicates that the connection properties have been updated.
+     * @param properties {object} - All available connection properties (e.g. shard, region).
+     */
+    PROPERTIES_UPDATED = 'connection.propertiesUpdated'
 }
 
 // exported for backward compatibility
 export const CONNECTION_REDIRECTED = JitsiConnectionEvents.CONNECTION_REDIRECTED;
 export const WRONG_STATE = JitsiConnectionEvents.WRONG_STATE;
 export const DISPLAY_NAME_REQUIRED = JitsiConnectionEvents.DISPLAY_NAME_REQUIRED;
+export const PROPERTIES_UPDATED = JitsiConnectionEvents.PROPERTIES_UPDATED;

modules/xmpp/xmpp.js

         }
 
         this.sendDeploymentInfo = false;
+
+        const { region, shard } = aprops;
+
+        if (region || shard) {
+            // avoids sending empty values
+            this.eventEmitter.emit(JitsiConnectionEvents.PROPERTIES_UPDATED, JSON.parse(JSON.stringify({
+                region,
+                shard
+            })));
+        }
+
     }
 }