fix: prevent unnecessary diagram re-rendering when editor changes are outside block#199
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ThisIs-Developer merged 2 commits intoJun 30, 2026
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Problem
Several diagram renderers (Markmap, PlantUML, Graphviz, D2, Vega-Lite, WaveDrom, ABC Notation) were re-rendering whenever any change was made anywhere in the Markdown editor, even if the change was outside the diagram’s fenced code block. This caused visual flickering, state loss (e.g., zoom/pan on Markmap), and unnecessary remote API calls.
This occurred because the DOM patching layer (
canReusePreviewNode) checked if theouterHTMLmatched. However, diagram shells generate a new random ID every time (e.g., viaMath.random()), making theouterHTMLcheck consistently fail.Solution
We updated
canReusePreviewNodeinscript.jsto look for diagram elements (containing adata-original-codeattribute) and reuse them if the source code and diagram engine class name are identical. This preserves the fully-rendered DOM nodes of the diagrams and prevents them from re-rendering on unrelated edits.