react-flow-best-practices

What this skill does

# React Flow Best Practices

## Purpose

Use this skill to review and improve React Flow implementations with the current `@xyflow/react` v12 patterns. Optimize for correctness first: stable node and handle IDs, typed node data, predictable viewport behavior, accessible controls, and performance that does not collapse as the workflow grows.

## First Steps

1. Inspect the React Flow package and usage:
   - `package.json` for `@xyflow/react`.
   - Global CSS for `@xyflow/react/dist/style.css`.
   - Canvas and node widget directories.
2. If API behavior is version-sensitive or uncertain, fetch current docs with Context7 for `React Flow` / `@xyflow/react` before recommending changes.
3. Choose the smallest reference file needed:
   - Canvas/state/viewport: read `references/canvas-state-and-viewport.md`.
   - Custom nodes, handles, toolbars, resizers, edges: read `references/custom-nodes-handles-and-edges.md`.
   - Review output checklist: read `references/review-checklist.md`.

## Review Workflow

1. Map the flow architecture before judging details.
   - Identify where domain data becomes `Node[]` and `Edge[]`.
   - Identify the `ReactFlow` wrapper, provider boundary, custom `nodeTypes`, custom `edgeTypes`, and global CSS import.
   - Confirm whether the canvas is static/narrative, editable, or partially interactive. This changes which issues matter.
2. Check identity contracts.
   - Node `id`, node `type`, handle `id`, `sourceHandle`, and `targetHandle` must line up exactly.
   - Edge ids should be deterministic from source/target/semantic relationship.
   - Changing these IDs is a migration-level change because saved flows, viewport focus, and edges can break.
3. Check state ownership.
   - Use controlled `nodes` and `edges` when the app needs domain-driven status, selection, persistence, or custom updates.
   - Preserve user moves/resizes unless the product intentionally rebuilds layout from domain state.
   - Keep frequent transient canvas state out of app-global stores unless another feature truly needs it.
4. Check custom components.
   - `nodeTypes` and `edgeTypes` must be defined outside render or memoized.
   - Custom nodes should use typed `NodeProps<Node<Data, "type">>` when practical.
   - Interactive controls inside nodes or edge labels need `nodrag`, `nopan`, and often `nowheel`.
5. Check viewport and accessibility.
   - Do not let auto-fit or status-driven focus override a user's manual pan/zoom after interaction.
   - Keep keyboard behavior deliberate: selection, multi-selection, pan activation, delete key, focusability.
   - Provide `ariaLabelConfig`, useful labels for custom controls, and visible selected/focused states.
6. Report findings with concrete risk.
   - Explain whether the issue can break edges, cause re-renders, trap interactions, override user viewport, or reduce accessibility.
   - Prefer small, local fixes that preserve existing visual language and architectural boundaries.

## Common Red Flags

- `nodeTypes` or `edgeTypes` object created inline inside a component render.
- Edges reference handle IDs that do not exist on the rendered node.
- Dynamic handles are added/removed without `useUpdateNodeInternals`.
- Node body contains buttons, inputs, scroll areas, or edge-label controls without `nodrag`/`nopan`/`nowheel`.
- `useReactFlow` is called outside `ReactFlowProvider` or outside children of `<ReactFlow>`.
- Parent container does not have an explicit height/width, causing an invisible canvas.
- Auto `fitView` runs on every data change and fights user pan/zoom.
- Whole `nodes` or `edges` arrays are subscribed to inside many node components.
- Custom edge labels are visually clickable but do not opt into pointer events or do not suppress pan/drag.
- Next.js server components import React Flow components without a client boundary.

## Documentation Base

This skill was created from:
- Context7 React Flow docs for `/websites/reactflow_dev`, queried for `@xyflow/react` v12 custom nodes, edges, handles, viewport controls, accessibility, and performance.

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