A five-year-old graph algorithm visualiser modernised with Claude Code

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Five years ago the poster spent 30 days building Graphisual, a graph algorithm visualiser. Revisiting it with Claude Code, he migrated the old Create React App project to React 19, Vite and Tailwind v4 without major problems.

As features were added, Opus 4.5 made things work by keeping state on the window object with custom events, so he used Plan Mode to move everything to zustand. He then iterated on an Excalidraw-inspired interface for creating, moving and connecting nodes, and on undo/redo, which ended up as a function wrapped around the zustand store.