A local-first note taking app
add lock to automerge editor to prevent race on debounce
Ethan Graf
(Jun 14, 2026, 10:57 PM EDT)
c063ef29
a624a8a9
+18
-21
+18
-21
src/editors/automerge/automergeDocumentEditor.tsx
+18
-21
src/editors/automerge/automergeDocumentEditor.tsx
···
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const readOnlyCompartment = useRef(new Compartment());
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-
// Echo suppression: when a local write is in flight, skip dispatching
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// the resulting change back into the editor.
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const isInFlightRef = useRef(false);
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-
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// Current content as a string, used for diff computation.
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const contentRef = useRef('');
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// Debounce timer for the save-based writer.
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const saveTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
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+
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// Lock: set while we are writing to the doc so the sync useEffect
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// can skip the round-trip back into the editor.
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const isWriting = useRef(false);
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// Version counter — bumped when the session notifies us of a doc change.
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const [docVersion, setDocVersion] = useState(0);
···
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// When the session loads/updates the doc, push the new content into CM6.
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useEffect(() => {
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const newContent = doc.content ?? '';
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-
contentRef.current = newContent;
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const view = viewRef.current;
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if (!view) return;
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if (isWriting.current) {
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isWriting.current = false;
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contentRef.current = newContent;
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return;
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}
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const currentText = view.state.doc.toString();
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if (currentText !== newContent) {
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view.dispatch({
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changes: { from: 0, to: currentText.length, insert: newContent },
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});
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}
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contentRef.current = newContent;
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}, [docVersion, doc.content]);
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// Create EditorView on mount.
···
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if (saveTimerRef.current) clearTimeout(saveTimerRef.current);
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saveTimerRef.current = setTimeout(() => {
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saveTimerRef.current = null;
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isInFlightRef.current = true;
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try {
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applyChangeRef.current((d) => {
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d.content = newContent;
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});
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} finally {
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isInFlightRef.current = false;
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}
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isWriting.current = true;
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applyChangeRef.current((d) => {
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d.content = newContent;
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});
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}, 50);
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}
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});
···
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clearTimeout(saveTimerRef.current);
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saveTimerRef.current = null;
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const finalContent = view.state.doc.toString();
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isInFlightRef.current = true;
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try {
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applyChangeRef.current((d) => {
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d.content = finalContent;
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});
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} finally {
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isInFlightRef.current = false;
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}
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applyChangeRef.current((d) => {
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d.content = finalContent;
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});
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}
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view.destroy();
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viewRef.current = null;