{
  "id": 9680720,
  "title": "What React Flow Doesn't Do For You: Building a Diagram Editor With Domain Rules",
  "url": "https://urgent.news/2026/09/25/what-react-flow-doesnt-do-for-you-building-a-diagram-editor-with",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-09-25T02:39:03.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/ruixuan_jiang_663eb75f3fa/what-react-flow-doesnt-do-for-you-building-a-diagram-editor-with-domain-rules-2e3o"
  },
  "original_language": "en",
  "account": "Building a diagram editor with domain rules in React Flow demanded more than just the library's basic features. While React Flow provided a canvas for panning, zooming, and viewport controls, along with a node/edge data model and selection/dragging capabilities, it did not inherently support the domain-specific rules necessary for a comprehensive genogram editor.\n\nNode rendering rules were one area where React Flow fell short. Genograms employ specialized shapes to represent individuals, encoding gender and health status within them. Custom node components utilizing SVG graphics were required to accurately render these elements within the React Flow canvas.\n\nEdge routing rules presented another challenge. Family relationships in genograms differ from mere connections. Partnerships are depicted with horizontal lines, while children descend from a midpoint on these lines. The midpoint shifts whenever partnerships are added or removed, necessitating edge geometry that adapts to the surrounding nodes rather than being stored directly per node pair. By utilizing custom edge components and defining edge types based on the domain model, React Flow could render these relationships correctly.\n\nReact Flow did not inherently distinguish between emotional and structural relationships in genograms. Emotional relationships required distinct line conventions, such as triple lines for close connections, zigzag lines for conflict, and dotted lines for distant relationships. Each line type necessitated a different edge component with specific path geometry and legend entries. This domain-specific classification of edges became the responsibility of the developer, rather than a feature provided by React Flow.\n\nTo enhance the user experience, a legend was implemented within the editor. The legend clarified the meaning behind each line convention used in the diagram, ensuring users understood the symbolism behind dashed, zigzag, and dotted lines. Creating a comprehensive legend required domain knowledge and careful consideration of the notation employed in genograms.\n\nPersistence posed an additional design challenge. Two storage modes were implemented: local projects using IndexedDB and cloud projects utilizing a different storage mechanism. Handling concurrent saves and ensuring data integrity required careful serialization of writes, preventing conflicts and race conditions. The autosave functionality was debounced, allowing for efficient storage updates without overloading the system. The export feature presented its own set of complexities, requiring the conversion of DOM elements representing nodes into a printable image format while maintaining the fidelity of the original design. Computing the bounding box, determining an appropriate scale factor, generating filenames, and handling nodes that fall outside the computed bounds were all considerations in the export process.\n\nOne of the most time-consuming aspects of building the genogram editor was ensuring the integrity and consistency of the domain model. The editor had to validate and migrate projects across different versions, safeguarding against schema changes and ensuring a seamless user experience. Proper error handling and migration strategies were implemented to gracefully handle scenarios where older projects were loaded or saved with incompatible schemas. The export feature required meticulous attention to detail, ensuring that the exported image accurately represented the diagram's layout, connections, and domain-specific conventions.\n\nIn summary, while React Flow provided a solid foundation for building a diagram editor, creating a domain-specific genogram editor demanded careful consideration of node rendering rules, edge routing rules, legend consistency, persistence strategies, and validation processes. By addressing these domain-specific requirements and implementing robust design patterns, a professional-grade editor capable of capturing the nuances of genograms could be achieved using React Flow as the underlying framework.",
  "summary": "I built a diagram editor for genograms. If you have not run into the term: a genogram is a diagram of a family that records more than descent. It uses standardized shapes for people and a set of line conventions for relationships, including emotional ones like closeness, distance, and conflict. The obvious library choice was React Flow ( @xyflow/react ). It is a good fit and I would choose it…",
  "key_points": [
    "React Flow provides canvas, node/edge data model, but lacks domain-specific rules for genograms",
    "Custom node components with SVG graphics required for specialized shapes representing individuals",
    "Custom edge components and edge types needed for accurate family relationship rendering in genograms"
  ],
  "editors_take": "Building a genogram editor with React Flow requires significant extension beyond the library's basic features to accommodate domain-specific rules, necessitating custom components, edge logic, and data validation.",
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}