chore(example): add debug node

example/src/Basic/DebugNode.tsx

@@ -0,0 +1,27 @@
+import { memo, FC, CSSProperties } from 'react';
+
+import { Handle, NodeProps, Position } from 'react-flow-renderer';
+
+const infoStyle: CSSProperties = { fontSize: 11 };
+const idStyle: CSSProperties = {
+  fontSize: 10,
+  color: '#888899',
+  position: 'absolute',
+  top: 2,
+  left: 2,
+};
+
+const ColorSelectorNode: FC<NodeProps> = ({ zIndex, xPos, yPos, id }) => {
+  return (
+    <>
+      <Handle type="target" position={Position.Top} />
+      <div style={idStyle}>{id}</div>
+      <div style={infoStyle}>
+        x:{Math.round(xPos || 0)} y:{Math.round(yPos || 0)} z:{zIndex}
+      </div>
+      <Handle type="source" position={Position.Bottom} />
+    </>
+  );
+};
+
+export default memo(ColorSelectorNode);