refactor(conenctionline): simplify getSourceHandle helper

package.json

@@ -82,4 +82,4 @@
     "dist",
     "nocss"
   ]
-}
+}

src/components/ConnectionLine/index.tsx

@@ -27,6 +27,14 @@ interface ConnectionLineProps {
   CustomConnectionLineComponent?: ConnectionLineComponent;
 }
 
+const getSourceHandle = (handleId: ElementId | null, sourceNode: Node, connectionHandleType: HandleType) => {
+  const handleTypeInverted = connectionHandleType === 'source' ? 'target' : 'source';
+  const handleBound =
+    sourceNode.__rf.handleBounds[connectionHandleType] || sourceNode.__rf.handleBounds[handleTypeInverted];
+
+  return handleId ? handleBound.find((d: HandleElement) => d.id === handleId) : handleBound[0];
+};
+
 export default ({
   connectionNodeId,
   connectionHandleId,
@@ -53,22 +61,7 @@ export default ({
     return null;
   }
 
-  const getSourceHandle = (handleId: ElementId | null, sourceNode: Node) => {
+  const sourceHandle = getSourceHandle(handleId, sourceNode, connectionHandleType);
-    const handleBound = sourceNode.__rf.handleBounds[connectionHandleType];
-    if (handleBound) {
-      if (handleId) {
-        return sourceNode.__rf.handleBounds[connectionHandleType].find((d: HandleElement) => d.id === handleId);
-      }
-      return sourceNode.__rf.handleBounds[connectionHandleType][0]
-    }
-    const handleType = connectionHandleType === 'source' ? 'target' : 'source';
-    if (handleId) {
-      return sourceNode.__rf.handleBounds[handleType].find((d: HandleElement) => d.id === handleId);
-    }
-    return sourceNode.__rf.handleBounds[handleType][0]
-  }
-
-  const sourceHandle = getSourceHandle(handleId, sourceNode);
   const sourceHandleX = sourceHandle ? sourceHandle.x + sourceHandle.width / 2 : sourceNode.__rf.width / 2;
   const sourceHandleY = sourceHandle ? sourceHandle.y + sourceHandle.height / 2 : sourceNode.__rf.height;
   const sourceX = sourceNode.__rf.position.x + sourceHandleX;
@@ -81,7 +74,6 @@ export default ({
   const targetPosition = isRightOrLeft ? Position.Left : Position.Top;
 
   if (CustomConnectionLineComponent) {
-
     return (
       <g className="react-flow__connection">
         <CustomConnectionLineComponent