react-flow-usage（React flow 使用）

React Flow Usage Guide

Comprehensive patterns and best practices for building production-ready node-based UIs with React Flow (@xyflow/react v12+).

When to Use This Skill

Apply these guidelines when:

• Building workflow editors, flow diagrams, or node-based interfaces
• Creating custom node or edge components
• Implementing drag-and-drop functionality for visual programming
• Optimizing performance for graphs with 100+ nodes
• Managing flow state, save/restore, or undo/redo
• Implementing auto-layout with dagre, elkjs, or custom algorithms
• Integrating React Flow with TypeScript

Rule Categories by Priority

Quick Start Pattern

import { useCallback } from 'react';
import {
  ReactFlow,
  Background,
  Controls,
  MiniMap,
  useNodesState,
  useEdgesState,
  addEdge
} from '@xyflow/react';
import '@xyflow/react/dist/style.css';

const initialNodes = [
  { id: '1', position: { x: 0, y: 0 }, data: { label: 'Node 1' } },
];

const initialEdges = [
  { id: 'e1-2', source: '1', target: '2' },
];

// Define outside component or use useMemo
const nodeTypes = { custom: CustomNode };
const edgeTypes = { custom: CustomEdge };

function Flow() {
  const [nodes, setNodes, onNodesChange] = useNodesState(initialNodes);
  const [edges, setEdges, onEdgesChange] = useEdgesState(initialEdges);

  const onConnect = useCallback(
    (params) => setEdges((eds) => addEdge(params, eds)),
    [setEdges]
  );

  return (
    <div style={{ width: '100%', height: '100vh' }}>
      <ReactFlow
        nodes={nodes}
        edges={edges}
        onNodesChange={onNodesChange}
        onEdgesChange={onEdgesChange}
        onConnect={onConnect}
        nodeTypes={nodeTypes}
        edgeTypes={edgeTypes}
        fitView
      >
        <Background />
        <Controls />
        <MiniMap />
      </ReactFlow>
    </div>
  );
}

Core Concepts Overview

Node Structure

• id: Unique identifier (required)
• position: {x: number, y: number} (required)
• data: Custom data object (required)
• type: Built-in or custom type
• style, className: Styling
• draggable, selectable, connectable: Interaction controls
• parentId: For nested/grouped nodes
• extent: Movement boundaries

Edge Structure

• id: Unique identifier (required)
• source: Source node id (required)
• target: Target node id (required)
• sourceHandle, targetHandle: Specific handle ids
• type: 'default' | 'straight' | 'step' | 'smoothstep' | custom
• animated: Boolean for animation
• label: String or React component
• markerStart, markerEnd: Arrow markers

Handle Usage

• Position: Position.Top | Bottom | Left | Right
• Type: 'source' | 'target'
• Multiple handles per node supported
• Use unique id prop for multiple handles

Essential Patterns

Custom Nodes

import { memo } from 'react';
import { Handle, Position, NodeProps } from '@xyflow/react';

const CustomNode = memo(({ data, selected }: NodeProps) => {
  return (
    <div className={`custom-node ${selected ? 'selected' : ''}`}>
      <Handle type="target" position={Position.Top} />
      <div>{data.label}</div>
      <Handle type="source" position={Position.Bottom} />
    </div>
  );
});

// IMPORTANT: Define outside component
const nodeTypes = { custom: CustomNode };

Custom Edges

import { BaseEdge, EdgeLabelRenderer, getBezierPath, EdgeProps } from '@xyflow/react';

function CustomEdge({ id, sourceX, sourceY, targetX, targetY, sourcePosition, targetPosition }: EdgeProps) {
  const [edgePath, labelX, labelY] = getBezierPath({
    sourceX, sourceY, sourcePosition, targetX, targetY, targetPosition,
  });

  return (
    <>
      <BaseEdge path={edgePath} />
      <EdgeLabelRenderer>
        <div style={{
          position: 'absolute',
          transform: `translate(-50%, -50%) translate(${labelX}px,${labelY}px)`,
        }}>
          Custom Label
        </div>
      </EdgeLabelRenderer>
    </>
  );
}

Performance Optimization

// 1. Memoize node/edge types (define outside component)
const nodeTypes = useMemo(() => ({ custom: CustomNode }), []);

// 2. Memoize callbacks
const onConnect = useCallback((params) =>
  setEdges((eds) => addEdge(params, eds)), [setEdges]
);

// 3. Use simple edge types for large graphs
const edgeType = nodes.length > 100 ? 'straight' : 'smoothstep';

// 4. Avoid unnecessary re-renders in custom components
const CustomNode = memo(({ data }) => <div>{data.label}</div>);

Key Hooks

• useReactFlow() - Access flow instance methods (getNodes, setNodes, fitView, etc.)
• useNodesState() / useEdgesState() - Managed state with change handlers
• useNodes() / useEdges() - Reactive access to current nodes/edges
• useNodesData(id) - Get specific node data (more performant than useNodes)
• useHandleConnections() - Get connections for a handle
• useConnection() - Track connection in progress
• useStore() - Direct store access (use sparingly)

Common Patterns

Drag and Drop

const onDrop = useCallback((event) => {
  event.preventDefault();
  const type = event.dataTransfer.getData('application/reactflow');
  const position = screenToFlowPosition({
    x: event.clientX,
    y: event.clientY,
  });

  setNodes((nds) => nds.concat({
    id: getId(),
    type,
    position,
    data: { label: `${type} node` },
  }));
}, [screenToFlowPosition]);

Save and Restore

const { toObject } = useReactFlow();

// Save
const flow = toObject();
localStorage.setItem('flow', JSON.stringify(flow));

// Restore
const flow = JSON.parse(localStorage.getItem('flow'));
setNodes(flow.nodes || []);
setEdges(flow.edges || []);
setViewport(flow.viewport);

Connection Validation

const isValidConnection = useCallback((connection) => {
  // Prevent self-connections
  if (connection.source === connection.target) return false;

  // Custom validation logic
  return true;
}, []);

Detailed Rules

For comprehensive patterns and best practices, see individual rule files in the rules/ directory organized by category:

rules/setup-*.md          - Critical setup patterns
rules/perf-*.md           - Performance optimization
rules/node-*.md           - Node customization patterns
rules/edge-*.md           - Edge handling patterns
rules/state-*.md          - State management
rules/hook-*.md           - Hooks usage
rules/layout-*.md         - Layout and positioning
rules/interaction-*.md    - User interactions
rules/typescript-*.md     - TypeScript integration

Full Compiled Documentation

For the complete guide with all rules and examples expanded: see AGENTS.md

Scraped Documentation Reference

Comprehensive scraped documentation from reactflow.dev is available in scraped/:

• Learn: scraped/learn-concepts/, scraped/learn-customization/, scraped/learn-advanced/
• API: scraped/api-hooks/, scraped/api-types/, scraped/api-utils/, scraped/api-components/
• Examples: scraped/examples-nodes/, scraped/examples-edges/, scraped/examples-interaction/, scraped/examples-layout/
• UI Components: scraped/ui-components/
• Tutorials: scraped/learn-tutorials/
• Troubleshooting: scraped/learn-troubleshooting/

Common Issues

1. Couldn't create edge - Add onConnect handler
2. Nodes not draggable - Check nodesDraggable prop
3. CSS not loading - Import @xyflow/react/dist/style.css
4. useReactFlow outside provider - Wrap with <ReactFlowProvider>
5. Performance issues - See Performance category rules
6. TypeScript errors - Use proper generic types useReactFlow<NodeType, EdgeType>()

References

• Official Documentation: https://reactflow.dev
• GitHub: https://github.com/xyflow/xyflow
• Package: @xyflow/react (npm)
• Examples: https://reactflow.dev/examples
• API Reference: https://reactflow.dev/api-reference