React Flow Implementation

Quick Start

import { useCallback } from 'react';
import { ReactFlow, 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' } },
  { id: '2', position: { x: 200, y: 100 }, data: { label: 'Node 2' } },
];

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

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

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

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

Implementation gates

Run these in order; do not skip ahead on “looks fine.”

1. Styles on the page — Pass if the bundle that renders <ReactFlow /> imports @xyflow/react/dist/style.css (or equivalent CSS pipeline) so nodes/edges are visible and hit-targets match visuals.
2. useReactFlow boundary — Pass if every caller of useReactFlow() is a descendant of <ReactFlowProvider> that wraps the same tree as <ReactFlow /> (or you have intentionally split stores and can name both roots).
3. Stable nodeTypes / edgeTypes — Pass if those maps are module-scope constants or useMemo with stable deps—not a new { ... } literal each render in the component that renders <ReactFlow />.
4. Handles match edges — Pass if for nodes with multiple Handle ids, every edge that must land on a specific handle sets sourceHandle / targetHandle accordingly (or you accept default handle resolution deliberately).

See ADDITIONAL_COMPONENTS.md for MiniMap, Controls, Background, NodeToolbar, and NodeResizer patterns.

Core Patterns

TypeScript Types

import type { Node, Edge, NodeProps, BuiltInNode } from '@xyflow/react';

// Define custom node type with data shape
type CustomNode = Node<{ value: number; label: string }, 'custom'>;

// Combine with built-in nodes
type MyNode = CustomNode | BuiltInNode;
type MyEdge = Edge<{ weight?: number }>;

// Use throughout app
const [nodes, setNodes] = useNodesState<MyNode>(initialNodes);

Custom Nodes

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

// Define node type
type CounterNode = Node<{ count: number }, 'counter'>;