feat: add drag n drop example

examples/DragNDrop/Sidebar.tsx

@@ -0,0 +1,25 @@
+const onDragStart = (event: DragEvent, nodeType: string) => {
+  if (event.dataTransfer) {
+    event.dataTransfer.setData('application/revueflow', nodeType);
+    event.dataTransfer.effectAllowed = 'move';
+  }
+};
+
+const Sidebar = () => {
+  return (
+    <aside>
+      <div class="description">You can drag these nodes to the pane on the left.</div>
+      <div class="revue-flow__node-input" onDragstart={(event: DragEvent) => onDragStart(event, 'input')} draggable>
+        Input Node
+      </div>
+      <div class="revue-flow__node-default" onDragstart={(event: DragEvent) => onDragStart(event, 'default')} draggable>
+        Default Node
+      </div>
+      <div class="revue-flow__node-output" onDragstart={(event: DragEvent) => onDragStart(event, 'output')} draggable>
+        Output Node
+      </div>
+    </aside>
+  );
+};
+
+export default Sidebar;

examples/DragNDrop/dnd.css

@@ -0,0 +1,37 @@
+.dndflow {
+  flex-direction: column;
+  display: flex;
+  height: 100%;
+}
+
+.dndflow aside {
+  border-right: 1px solid #eee;
+  padding: 15px 10px;
+  font-size: 12px;
+  background: #fcfcfc;
+}
+
+.dndflow aside > * {
+  margin-bottom: 10px;
+  cursor: grab;
+}
+
+.dndflow aside .description {
+  margin-bottom: 10px;
+}
+
+.dndflow .revueflow-wrapper {
+  flex-grow: 1;
+  height: 100%;
+}
+
+@media screen and (min-width: 768px) {
+  .dndflow {
+    flex-direction: row;
+  }
+
+  .dndflow aside {
+    width: 20%;
+    max-width: 180px;
+  }
+}

examples/DragNDrop/index.tsx

@@ -0,0 +1,77 @@
+import RevueFlow, {
+  addEdge,
+  removeElements,
+  Controls,
+  OnLoadParams,
+  Elements,
+  Connection,
+  Edge,
+  ElementId,
+  Node
+} from '../../src';
+import Sidebar from './Sidebar';
+
+import './dnd.css';
+import { defineComponent, ref } from 'vue';
+
+const initialElements = [{ id: '1', type: 'input', data: { label: 'input node' }, position: { x: 250, y: 5 } }];
+
+const onDragOver = (event: DragEvent) => {
+  event.preventDefault();
+  if (event.dataTransfer) {
+    event.dataTransfer.dropEffect = 'move';
+  }
+};
+
+let id = 0;
+const getId = (): ElementId => `dndnode_${id++}`;
+
+const DnDFlow = defineComponent({
+  setup() {
+    const revueFlowInstance = ref<OnLoadParams>();
+    const elements = ref<Elements>(initialElements);
+
+    const onConnect = (params: Connection | Edge) => (elements.value = addEdge(params, elements.value));
+    const onElementsRemove = (elementsToRemove: Elements) => (elements.value = removeElements(elementsToRemove, elements.value));
+    const onLoad = (instance: OnLoadParams) => (revueFlowInstance.value = instance);
+
+    const onDrop = (event: DragEvent) => {
+      event.preventDefault();
+
+      if (revueFlowInstance.value) {
+        console.log(event.dataTransfer?.getData('application/revueflow'));
+        const type = event.dataTransfer?.getData('application/revueflow');
+        const position = revueFlowInstance.value.project({ x: event.clientX, y: event.clientY - 40 });
+        const newNode: Node = {
+          id: getId(),
+          type,
+          position,
+          data: { label: `${type} node` }
+        };
+
+        elements.value.push(newNode);
+        console.log(elements.value);
+      }
+    };
+
+    return () => (
+      <div class="dndflow">
+        <div class="revueflow-wrapper">
+          <RevueFlow
+            elements={elements.value}
+            onConnect={onConnect}
+            onElementsRemove={onElementsRemove}
+            onLoad={onLoad}
+            onDrop={onDrop}
+            onDragover={onDragOver}
+          >
+            <Controls />
+          </RevueFlow>
+        </div>
+        <Sidebar />
+      </div>
+    );
+  }
+});
+
+export default DnDFlow;

examples/router.ts

@@ -12,6 +12,10 @@ export const routes = [
   {
     path: '/custom-node',
     component: () => import('./CustomNode')
+  },
+  {
+    path: '/drag-n-drop',
+    component: () => import('./DragNDrop')
   }
 ];