Cleanup of jasonpul's connection-validation branch

example/src/CustomNode/ColorSelectorNode.js

@@ -15,8 +15,8 @@ export default memo(({ data }) => {
         Custom Color Picker Node: <strong>{data.color}</strong>
       </div>
       <input className="nodrag" type="color" onChange={data.onChange} defaultValue={data.color} />
-      <Handle type="source" position="right" id="a" style={{ top: 10, background: '#555' }} />
-      <Handle type="source" position="right" id="b" style={{ bottom: 10, top: 'auto', background: '#555' }} />
+      <Handle type="source" position="right" id="0" style={{ top: 10, background: '#555' }} />
+      <Handle type="source" position="right" id="1" style={{ bottom: 10, top: 'auto', background: '#555' }} />
     </>
   );
 });

example/src/CustomNode/index.js

@@ -56,8 +56,8 @@ const CustomNodeFlow = () => {
       { id: '4', type: 'output', data: { label: 'Output B' }, position: { x: 550, y: 100 }, targetPosition: 'left' },
 
       { id: 'e1-2', source: '1', target: '2', animated: true, style: { stroke: '#fff' } },
-      { id: 'e2a-3', source: '2__a', target: '3', animated: true, style: { stroke: '#fff' } },
-      { id: 'e2b-4', source: '2__b', target: '4', animated: true, style: { stroke: '#fff' } },
+      { id: 'e2a-3', source: '2', sourceHandle: '0', target: '3', animated: true, style: { stroke: '#fff' } },
+      { id: 'e2b-4', source: '2', sourceHandle: '1', target: '4', animated: true, style: { stroke: '#fff' } },
     ]);
   }, []);
 

example/src/Validation/index.js

@@ -20,7 +20,7 @@ const onConnectEnd = (event) => console.log('on connect end', event);
 const CustomInput = () => (
   <>
     <div>Only connectable with B</div>
-    <Handle type="source" position="right" isValidConnection={isValidConnection} />
+    <Handle type="source" position="right" id="a" isValidConnection={isValidConnection} />
   </>
 );
 

src/components/Handle/BaseHandle.tsx

@@ -42,6 +42,7 @@ type Result = {
 
 function onMouseDown(
   event: ReactMouseEvent,
+  handleId: ElementId,
   nodeId: ElementId,
   setConnectionNodeId: SetSourceIdFunc,
   setPosition: (pos: XYPosition) => void,
@@ -88,26 +89,30 @@ function onMouseDown(
     const result: Result = {
       elementBelow,
       isValid: false,
-      connection: { source: null, target: null },
+      connection: { source: null, target: null, sourceHandle: null, targetHandle: null },
       isHoveringHandle: false,
     };
 
     if (elementBelow && (elementBelow.classList.contains('target') || elementBelow.classList.contains('source'))) {
-      let connection: Connection = { source: null, target: null };
-
-      if (isTarget) {
-        const sourceId = elementBelow.getAttribute('data-nodeid');
-        connection = { source: sourceId, target: nodeId };
-      } else {
-        const targetId = elementBelow.getAttribute('data-nodeid');
-        connection = { source: nodeId, target: targetId };
-      }
-
-      const isValid = isValidConnection(connection);
-
-      result.connection = connection;
-      result.isValid = isValid;
       result.isHoveringHandle = true;
+      if ((isTarget && elementBelow.classList.contains('source')) || (!isTarget && elementBelow.classList.contains('target'))) {
+        let connection: Connection = { source: null, target: null, sourceHandle: null, targetHandle: null };
+
+        if (isTarget) {
+          const sourceId = elementBelow.getAttribute('data-nodeid');
+          const sourcehandleId = elementBelow.getAttribute('data-handleid');
+          connection = { source: sourceId, sourceHandle: sourcehandleId, target: nodeId, targetHandle: handleId };
+        } else {
+          const targetId = elementBelow.getAttribute('data-nodeid');
+          const targetHandleId = elementBelow.getAttribute('data-handleid');
+          connection = { source: nodeId, sourceHandle: handleId, target: targetId , targetHandle: targetHandleId};
+        }
+
+        const isValid = isValidConnection(connection);
+
+        result.connection = connection;
+        result.isValid = isValid;
+      }
     }
 
     return result;
@@ -187,17 +192,18 @@ const BaseHandle = ({
     },
   ]);
 
-  const nodeIdWithHandleId = id ? `${nodeId}__${id}` : nodeId;
-
+  const handleId = id ? `${id}`: ''
   return (
     <div
-      data-nodeid={nodeIdWithHandleId}
+      data-handleid={handleId}
+      data-nodeid={nodeId}
       data-handlepos={position}
       className={handleClasses}
       onMouseDown={(event) =>
         onMouseDown(
           event,
-          nodeIdWithHandleId,
+          handleId,
+          nodeId,
           setConnectionNodeId,
           setPosition,
           onConnect,

src/components/Nodes/utils.ts

@@ -19,15 +19,8 @@ export const getHandleBounds = (
     (handle): HandleElement => {
       const bounds = handle.getBoundingClientRect();
       const dimensions = getDimensions(handle);
-      const nodeIdAttr = handle.getAttribute('data-nodeid');
+      const handleId = handle.getAttribute('data-handleid');
       const handlePosition = (handle.getAttribute('data-handlepos') as unknown) as Position;
-      const nodeIdSplitted = nodeIdAttr ? nodeIdAttr.split('__') : null;
-
-      let handleId = null;
-
-      if (nodeIdSplitted) {
-        handleId = (nodeIdSplitted.length ? nodeIdSplitted[1] : nodeIdSplitted) as string;
-      }
 
       return {
         id: handleId,

src/container/EdgeRenderer/index.tsx

@@ -132,8 +132,10 @@ function renderEdge(
   selectedElements: Elements | null,
   elementsSelectable: boolean
 ) {
-  const [sourceId, sourceHandleId] = edge.source.split('__');
-  const [targetId, targetHandleId] = edge.target.split('__');
+  const sourceId = edge.source
+  const sourceHandleId = edge.sourceHandle!
+  const targetId = edge.target
+  const targetHandleId = edge.targetHandle!
 
   const sourceNode = nodes.find((n) => n.id === sourceId);
   const targetNode = nodes.find((n) => n.id === targetId);

src/types/index.ts

@@ -60,6 +60,8 @@ export interface Edge {
   type?: string;
   source: ElementId;
   target: ElementId;
+  sourceHandle?: ElementId;
+  targetHandle?: ElementId;
   label?: string;
   labelStyle?: CSSProperties;
   labelShowBg?: boolean;
@@ -243,6 +245,8 @@ export type OnLoadFunc = (params: OnLoadParams) => void;
 export interface Connection {
   source: ElementId | null;
   target: ElementId | null;
+  sourceHandle: ElementId | null;
+  targetHandle: ElementId | null;
 }
 
 export enum ConnectionLineType {

src/utils/graph.ts

@@ -40,7 +40,19 @@ export const removeElements = (elementsToRemove: Elements, elements: Elements):
   });
 };
 
-const getEdgeId = ({ source, target }: Connection): ElementId => `reactflow__edge-${source}-${target}`;
+const getEdgeId = ({ source, sourceHandle, target, targetHandle }: Connection): ElementId => `reactflow__edge-${source}${sourceHandle}-${target}${targetHandle}`;
+
+const existingConnection = (edge: Edge, elements: Elements) => {
+  for (const element of elements) {
+    if (isEdge(element)) {
+      if (element.source === edge.source && element.sourceHandle === edge.sourceHandle && element.target === edge.target && element.targetHandle === edge.targetHandle) {
+        return true
+      }
+    }
+  }
+  return false
+}
+
 
 export const addEdge = (edgeParams: Edge | Connection, elements: Elements): Elements => {
   if (!edgeParams.source || !edgeParams.target) {
@@ -49,22 +61,31 @@ export const addEdge = (edgeParams: Edge | Connection, elements: Elements): Elem
 
   // make sure that there is node with the target and one with the source id
   [edgeParams.source, edgeParams.target].forEach((id) => {
-    const nodeId = id.includes('__') ? id.split('__')[0] : id;
-    if (!elements.find((e) => isNode(e) && e.id === nodeId)) {
-      throw new Error(`Can't create edge. Node with id=${nodeId} does not exist.`);
+    if (!elements.find((e) => isNode(e) && e.id === id)) {
+      throw new Error(`Can't create edge. Node with id=${id} does not exist.`);
     }
   });
 
+  // make sure that the handles exists in each node
+  const handleElements = Array.from(document.getElementsByClassName("react-flow__handle")) as HTMLDivElement[]
+  [[edgeParams.source, edgeParams.sourceHandle], [edgeParams.target, edgeParams.targetHandle]].forEach(([nodeId, handleId]) => {
+    if (!handleElements.find((he) => he.getAttribute('data-nodeid') === nodeId && he.getAttribute('data-handleid') === handleId)) {
+      throw new Error(`Can't create edge. Handle with id=${handleId} does not exist within Node with id=${nodeId}.`);
+    }
+  })
+
+  let edge: Edge
   if (isEdge(edgeParams)) {
-    return elements.concat({ ...edgeParams });
+    edge = {...edgeParams}
+  } else {
+    edge = {
+      ...edgeParams,
+      id: getEdgeId(edgeParams),
+    } as Edge;
   }
 
-  const edge = {
-    ...edgeParams,
-    id: getEdgeId(edgeParams),
-  } as Edge;
-
-  return elements.concat(edge);
+  if (existingConnection(edge, elements)) {return elements}
+  return elements.concat(edge)
 };
 
 export const pointToRendererPoint = (
@@ -112,6 +133,8 @@ export const parseElement = (element: Node | Edge): Node | Edge => {
       ...element,
       source: element.source.toString(),
       target: element.target.toString(),
+      sourceHandle: element.sourceHandle ? element.sourceHandle.toString() : '',
+      targetHandle: element.targetHandle ? element.targetHandle.toString() : '',
       id: element.id.toString(),
       type: element.type || 'default',
     };