fix(edges): Check if connection exists for new connection

package/src/components/Edges/EdgeWrapper.vue

@@ -70,7 +70,7 @@ const handleEdgeUpdater = (event: MouseEvent, isSourceHandle: boolean) => {
     undefined,
     isSourceHandle ? 'target' : 'source',
     (connection) => {
-      if (!connectionExists(edge, getEdges)) emits.edgeUpdate({ edge, connection })
+      if (!connectionExists(connection, getEdges)) emits.edgeUpdate({ edge, connection })
     },
     () => emits.edgeUpdateEnd({ event, edge }),
   )
@@ -172,7 +172,7 @@ export default {
   <g
     :class="getClass()"
     @click="onEdgeClick"
-    @dblClick="onDoubleClick"
+    @dbl-click="onDoubleClick"
     @contextmenu="onEdgeContextMenu"
     @mouseenter="onEdgeMouseEnter"
     @mousemove="onEdgeMouseMove"

package/src/utils/graph.ts

@@ -129,7 +129,7 @@ export const getIncomers = (node: GraphNode, elements: Elements) => getConnected
 export const getEdgeId = ({ source, sourceHandle, target, targetHandle }: Connection) =>
   `vueflow__edge-${source}${sourceHandle ?? ''}-${target}${targetHandle ?? ''}`
 
-export const connectionExists = (edge: Edge, elements: Elements) =>
+export const connectionExists = (edge: Edge | Connection, elements: Elements) =>
   elements.some(
     (el) =>
       isEdge(el) &&