refactor(drag-edge): cleanup drag edge handlers

src/components/Edges/wrapEdge.tsx

@@ -2,7 +2,8 @@ import React, { memo, ComponentType, useCallback } from 'react';
 import cc from 'classcat';
 
 import { useStoreActions } from '../../store/hooks';
-import { Edge, EdgeProps, WrapEdgeProps } from '../../types';
+import { Edge, EdgeProps, WrapEdgeProps, Connection } from '../../types';
+import { onMouseDown } from '../../components/Handle/BaseHandle';
 
 export default (EdgeComponent: ComponentType<EdgeProps>) => {
   const EdgeWrapper = ({
@@ -32,9 +33,13 @@ export default (EdgeComponent: ComponentType<EdgeProps>) => {
     elementsSelectable,
     markerEndId,
     isHidden,
-    onEitherEndOfEdgePress,
+    sourceHandleId,
+    targetHandleId,
+    onEdgeUpdate,
   }: WrapEdgeProps) => {
     const addSelectedElements = useStoreActions((actions) => actions.addSelectedElements);
+    const setConnectionNodeId = useStoreActions((actions) => actions.setConnectionNodeId);
+    const setPosition = useStoreActions((actions) => actions.setConnectionPosition);
 
     const inactive = !elementsSelectable && !onClick;
     const edgeClasses = cc([
@@ -63,35 +68,46 @@ export default (EdgeComponent: ComponentType<EdgeProps>) => {
       [elementsSelectable, id, source, target, type, data, onClick]
     );
 
-    const handleEdgeUpdaterMouseDown = useCallback(
+    const handleEdgeUpdater = useCallback(
-      (event: React.MouseEvent<SVGGElement, MouseEvent>, isEdgeHeader?: boolean): void => {
+      (event: React.MouseEvent<SVGGElement, MouseEvent>, isSourceHandle: boolean) => {
-        if (elementsSelectable) {
+        const nodeId = isSourceHandle ? target : source;
-          addSelectedElements({ id, source, target });
+        const handleId = isSourceHandle ? targetHandleId : sourceHandleId;
-        }
 
-        const edgeElement: Edge = { id, source, target, type };
+        const onConnect = (connection: Connection) => {
+          if (onEdgeUpdate) {
+            const edgeElement: Edge = {
+              id,
+              source,
+              target,
+              sourceHandle: sourceHandleId,
+              targetHandle: targetHandleId,
+              type,
+            };
 
-        if (typeof data !== 'undefined') {
+            onEdgeUpdate(edgeElement, connection);
-          edgeElement.data = data;
+          }
-        }
+        };
 
-        onEitherEndOfEdgePress(event, edgeElement, isEdgeHeader);
+        const isValidConnection = () => true;
+        const isTarget = isSourceHandle;
+
+        onMouseDown(event, handleId, nodeId, setConnectionNodeId, setPosition, onConnect, isTarget, isValidConnection);
       },
-      [elementsSelectable, id, source, target, type, data, onEitherEndOfEdgePress]
+      [id, source, target, type, sourceHandleId, targetHandleId, setConnectionNodeId, setPosition]
     );
 
-    const handleEdgeTargetMouseDown = useCallback(
+    const onEdgeUpdaterSourceMouseDown = useCallback(
       (event: React.MouseEvent<SVGGElement, MouseEvent>): void => {
-        handleEdgeUpdaterMouseDown(event, true);
+        handleEdgeUpdater(event, true);
       },
-      [handleEdgeUpdaterMouseDown]
+      [id, source, sourceHandleId, handleEdgeUpdater]
     );
 
-    const handleEdgeSourceMouseDown = useCallback(
+    const onEdgeUpdaterTargetMouseDown = useCallback(
       (event: React.MouseEvent<SVGGElement, MouseEvent>): void => {
-        handleEdgeUpdaterMouseDown(event);
+        handleEdgeUpdater(event, false);
       },
-      [handleEdgeUpdaterMouseDown]
+      [id, target, targetHandleId, handleEdgeUpdater]
     );
 
     if (isHidden) {
@@ -100,7 +116,7 @@ export default (EdgeComponent: ComponentType<EdgeProps>) => {
 
     return (
       <g className={edgeClasses} onClick={onEdgeClick}>
-        <g onMouseDown={handleEdgeSourceMouseDown}>
+        <g onMouseDown={onEdgeUpdaterSourceMouseDown}>
           <circle
             className="react-flow__edgeupdater"
             cx={sourceX}
@@ -133,7 +149,7 @@ export default (EdgeComponent: ComponentType<EdgeProps>) => {
           targetPosition={targetPosition}
           markerEndId={markerEndId}
         />
-        <g onMouseDown={handleEdgeTargetMouseDown}>
+        <g onMouseDown={onEdgeUpdaterTargetMouseDown}>
           <circle
             className="react-flow__edgeupdater"
             cx={targetX}

src/container/EdgeRenderer/index.tsx

@@ -1,6 +1,6 @@
 import React, { memo, CSSProperties } from 'react';
 
-import { useStoreState, useStoreActions } from '../../store/hooks';
+import { useStoreState } from '../../store/hooks';
 import ConnectionLine from '../../components/ConnectionLine/index';
 import { isEdge } from '../../utils/graph';
 import MarkerDefinitions from './MarkerDefinitions';
@@ -14,10 +14,8 @@ import {
   Elements,
   ConnectionLineType,
   ConnectionLineComponent,
-  Connection,
   OnEdgeUpdateFunc,
 } from '../../types';
-import { onMouseDown, SetSourceIdFunc } from '../../components/Handle/BaseHandle';
 
 interface EdgeRendererProps {
   edgeTypes: any;
@@ -138,9 +136,7 @@ function renderEdge(
   props: EdgeRendererProps,
   nodes: Node[],
   selectedElements: Elements | null,
-  elementsSelectable: boolean,
+  elementsSelectable: boolean
-  setConnectionNodeId: SetSourceIdFunc,
-  setPosition: (pos: XYPosition) => void
 ) {
   const sourceId = edge.source;
   const sourceHandleId = edge.sourceHandle || null;
@@ -192,22 +188,6 @@ function renderEdge(
 
   const isSelected = selectedElements ? selectedElements.some((elm) => isEdge(elm) && elm.id === edge.id) : false;
 
-  const onConnect = (connection: Connection) => {
-    const { onEdgeUpdate } = props;
-    if (onEdgeUpdate) {
-      onEdgeUpdate(edge, connection);
-    }
-  };
-
-  const handleEitherEndOfEdgePress = (event: React.MouseEvent, edge: Edge, isEdgeHeader = false) => {
-    const { source, target } = edge;
-    const nodeId = isEdgeHeader ? source : target;
-    const isValidConnection = () => true;
-    const isTarget = !isEdgeHeader;
-
-    onMouseDown(event, null, nodeId, setConnectionNodeId, setPosition, onConnect, isTarget, isValidConnection);
-  };
-
   return (
     <EdgeComponent
       key={edge.id}
@@ -239,7 +219,6 @@ function renderEdge(
       elementsSelectable={elementsSelectable}
       markerEndId={props.markerEndId}
       isHidden={edge.isHidden}
-      onEitherEndOfEdgePress={handleEitherEndOfEdgePress}
     />
   );
 }
@@ -257,8 +236,6 @@ const EdgeRenderer = (props: EdgeRendererProps) => {
   const elementsSelectable = useStoreState((state) => state.elementsSelectable);
   const width = useStoreState((state) => state.width);
   const height = useStoreState((state) => state.height);
-  const setConnectionNodeId = useStoreActions((actions) => actions.setConnectionNodeId);
-  const setPosition = useStoreActions((actions) => actions.setConnectionPosition);
 
   const { connectionLineType, arrowHeadColor, connectionLineStyle, connectionLineComponent } = props;
 
@@ -273,9 +250,7 @@ const EdgeRenderer = (props: EdgeRendererProps) => {
     <svg width={width} height={height} className="react-flow__edges">
       <MarkerDefinitions color={arrowHeadColor} />
       <g transform={transformStyle}>
-        {edges.map((edge: Edge) =>
+        {edges.map((edge: Edge) => renderEdge(edge, props, nodes, selectedElements, elementsSelectable))}
-          renderEdge(edge, props, nodes, selectedElements, elementsSelectable, setConnectionNodeId, setPosition)
-        )}
         {renderConnectionLine && (
           <ConnectionLine
             nodes={nodes}

src/types/index.ts

@@ -111,7 +111,8 @@ export interface WrapEdgeProps {
   arrowHeadType?: ArrowHeadType;
   source: ElementId;
   target: ElementId;
-  sourceHandleId?: string;
+  sourceHandleId: ElementId | null;
+  targetHandleId: ElementId | null;
   sourceX: number;
   sourceY: number;
   targetX: number;
@@ -121,7 +122,7 @@ export interface WrapEdgeProps {
   elementsSelectable?: boolean;
   markerEndId?: string;
   isHidden?: boolean;
-  onEitherEndOfEdgePress: (event: React.MouseEvent, edge: Edge, isEdgeHeader?: boolean) => void;
+  onEdgeUpdate?: OnEdgeUpdateFunc;
 }
 
 export interface EdgeProps {

src/utils/graph.ts

@@ -82,16 +82,8 @@ export const updateEdge = (oldEdge: Edge, newConnection: Connection, elements: E
     throw new Error("Can't create new edge. An edge needs a source and a target.");
   }
 
-  // make sure that there is node with the target and one with the source id
+  const foundEdge = elements.find((e) => isEdge(e) && e.id === oldEdge.id) as Edge;
-  [newConnection.source, newConnection.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=${nodeId} does not exist.`);
-    }
-  });
-  
-  const foundEdge = elements.find(e => isEdge(e) && e.id === oldEdge.id) as Edge;
   if (!foundEdge) {
     throw new Error(`The old edge with id=${oldEdge.id} does not exist.`);
   }
@@ -104,10 +96,9 @@ export const updateEdge = (oldEdge: Edge, newConnection: Connection, elements: E
     target: newConnection.target,
   } as Edge;
 
-  return elements.filter(e => e.id !== oldEdge.id).concat(edge);
+  return elements.filter((e) => e.id !== oldEdge.id).concat(edge);
 };
 
-
 export const pointToRendererPoint = (
   { x, y }: XYPosition,
   [tx, ty, tScale]: Transform,