Merge branch 'main' into worktree-perf

apps/yaak-client/components/GrpcRequestPane.tsx

@@ -1,4 +1,4 @@
-import { type GrpcRequest, type HttpRequestHeader, patchModel } from "@yaakapp-internal/models";
+import { type GrpcRequest, type HttpRequestHeader, patchModel, patchModelDebounced} from "@yaakapp-internal/models";
 import { HStack, Icon, useContainerSize, VStack } from "@yaakapp-internal/ui";
 import classNames from "classnames";
 import type { CSSProperties } from "react";
@@ -75,11 +75,13 @@ export function GrpcRequestPane({
   const { width: paneWidth } = useContainerSize(urlContainerEl);
 
   const handleChangeUrl = useCallback(
-    (url: string) => patchModel(activeRequest, { url }),
+    (url: string) => patchModelDebounced(activeRequest, { url }),
     [activeRequest],
   );
 
   const handleChangeMessage = useCallback(
+    // Not debounced: handleSend reads message from the store, so a pending
+    // debounced patch would send stale text
     (message: string) => patchModel(activeRequest, { message }),
     [activeRequest],
   );
@@ -146,12 +148,12 @@ export function GrpcRequestPane({
   );
 
   const handleMetadataChange = useCallback(
-    (metadata: HttpRequestHeader[]) => patchModel(activeRequest, { metadata }),
+    (metadata: HttpRequestHeader[]) => patchModelDebounced(activeRequest, { metadata }),
     [activeRequest],
   );
 
   const handleDescriptionChange = useCallback(
-    (description: string) => patchModel(activeRequest, { description }),
+    (description: string) => patchModelDebounced(activeRequest, { description }),
     [activeRequest],
   );
 
@@ -299,7 +301,7 @@ export function GrpcRequestPane({
               className="font-sans text-xl! px-0!"
               containerClassName="border-0"
               placeholder={resolvedModelName(activeRequest)}
-              onChange={(name) => patchModel(activeRequest, { name })}
+              onChange={(name) => patchModelDebounced(activeRequest, { name })}
             />
             <MarkdownEditor
               name="request-description"

apps/yaak-client/components/HttpRequestPane.tsx

@@ -1,12 +1,11 @@
 import type { HttpRequest } from "@yaakapp-internal/models";
-import { patchModel } from "@yaakapp-internal/models";
+import { patchModel, patchModelDebounced } from "@yaakapp-internal/models";
 import type { GenericCompletionOption } from "@yaakapp-internal/plugins";
 import classNames from "classnames";
 import { atom, useAtomValue } from "jotai";
 import type { CSSProperties } from "react";
 import { lazy, Suspense, useCallback, useMemo, useRef, useState } from "react";
-import { activeRequestIdAtom } from "../hooks/useActiveRequestId";
-import { allRequestsAtom } from "../hooks/useAllRequests";
+import { allRequestUrlsAtom } from "../hooks/useAllRequests";
 import { useAuthTab } from "../hooks/useAuthTab";
 import { useCancelHttpResponse } from "../hooks/useCancelHttpResponse";
 import { useHeadersTab } from "../hooks/useHeadersTab";
@@ -16,7 +15,6 @@ import { usePinnedHttpResponse } from "../hooks/usePinnedHttpResponse";
 import { useRequestEditor, useRequestEditorEvent } from "../hooks/useRequestEditor";
 import { useRequestUpdateKey } from "../hooks/useRequestUpdateKey";
 import { useSendAnyHttpRequest } from "../hooks/useSendAnyHttpRequest";
-import { deepEqualAtom } from "../lib/atoms";
 import { languageFromContentType } from "../lib/contentType";
 import { generateId } from "../lib/generateId";
 import { extractPathPlaceholders } from "../lib/pathPlaceholders";
@@ -77,15 +75,12 @@ const TAB_SETTINGS = "settings";
 const TAB_DESCRIPTION = "description";
 const TABS_STORAGE_KEY = "http_request_tabs";
 
-const nonActiveRequestUrlsAtom = atom((get) => {
-  const activeRequestId = get(activeRequestIdAtom);
-  const requests = get(allRequestsAtom);
-  return requests
-    .filter((r) => r.id !== activeRequestId)
-    .map((r): GenericCompletionOption => ({ type: "constant", label: r.url }));
-});
-
-const memoNotActiveRequestUrlsAtom = deepEqualAtom(nonActiveRequestUrlsAtom);
+// Derived from the identity-stable URL list so this only recomputes when a URL
+// actually changes. The active request's own URL is included, but exact matches
+// are filtered out at completion time by genericCompletion.
+const requestUrlOptionsAtom = atom((get): GenericCompletionOption[] =>
+  get(allRequestUrlsAtom).map((url) => ({ type: "constant", label: url })),
+);
 
 export function HttpRequestPane({ style, fullHeight, className, activeRequest }: Props) {
   const activeRequestId = activeRequest.id;
@@ -274,16 +269,16 @@ export function HttpRequestPane({ style, fullHeight, className, activeRequest }:
   const { mutate: importCurl } = useImportCurl();
 
   const handleBodyChange = useCallback(
-    (body: HttpRequest["body"]) => patchModel(activeRequest, { body }),
+    (body: HttpRequest["body"]) => patchModelDebounced(activeRequest, { body }),
     [activeRequest],
   );
 
   const handleBodyTextChange = useCallback(
-    (text: string) => patchModel(activeRequest, { body: { ...activeRequest.body, text } }),
+    (text: string) => patchModelDebounced(activeRequest, { body: { ...activeRequest.body, text } }),
     [activeRequest],
   );
 
-  const autocompleteUrls = useAtomValue(memoNotActiveRequestUrlsAtom);
+  const autocompleteUrls = useAtomValue(requestUrlOptionsAtom);
 
   const autocomplete: GenericCompletionConfig = useMemo(
     () => getUrlCompletionConfig(autocompleteUrls),
@@ -323,7 +318,7 @@ export function HttpRequestPane({ style, fullHeight, className, activeRequest }:
   );
 
   const handleUrlChange = useCallback(
-    (url: string) => patchModel(activeRequest, { url }),
+    (url: string) => patchModelDebounced(activeRequest, { url }),
     [activeRequest],
   );
 
@@ -369,7 +364,7 @@ export function HttpRequestPane({ style, fullHeight, className, activeRequest }:
                 forceUpdateKey={`${forceUpdateHeaderEditorKey}::${forceUpdateKey}`}
                 headers={activeRequest.headers}
                 stateKey={`headers.${activeRequest.id}`}
-                onChange={(headers) => patchModel(activeRequest, { headers })}
+                onChange={(headers) => patchModelDebounced(activeRequest, { headers })}
               />
             </TabContent>
             <TabContent value={TAB_PARAMS}>
@@ -377,7 +372,7 @@ export function HttpRequestPane({ style, fullHeight, className, activeRequest }:
                 stateKey={`params.${activeRequest.id}`}
                 forceUpdateKey={forceUpdateKey + urlParametersKey}
                 pairs={urlParameterPairs}
-                onChange={(urlParameters) => patchModel(activeRequest, { urlParameters })}
+                onChange={(urlParameters) => patchModelDebounced(activeRequest, { urlParameters })}
               />
             </TabContent>
             <TabContent value={TAB_SETTINGS}>
@@ -429,7 +424,7 @@ export function HttpRequestPane({ style, fullHeight, className, activeRequest }:
                     requestId={activeRequest.id}
                     contentType={contentType}
                     body={activeRequest.body}
-                    onChange={(body) => patchModel(activeRequest, { body })}
+                    onChange={(body) => patchModelDebounced(activeRequest, { body })}
                     onChangeContentType={handleContentTypeChange}
                   />
                 ) : typeof activeRequest.bodyType === "string" ? (

apps/yaak-client/components/Sidebar.tsx

@@ -112,6 +112,7 @@ function Sidebar({ className }: { className?: string }) {
   const treeId = `tree.${activeWorkspaceId ?? "unknown"}`;
   const filterText = useAtomValue(sidebarFilterAtom);
   const [tree, allFields, emptyFilterSuggestions] = useAtomValue(sidebarTreeAtom) ?? [];
+
   const wrapperRef = useRef<HTMLElement>(null);
   const treeRef = useRef<TreeHandle>(null);
   const filterRef = useRef<InputHandle>(null);
@@ -724,7 +725,11 @@ function Sidebar({ className }: { className?: string }) {
   );
 }
 
-export default Sidebar;
+// Memoized so route navigations (which re-render the workspace layout) don't
+// re-render the sidebar subtree. In large workspaces a sidebar re-render is
+// very expensive: it re-renders DndContext, whose context churn re-renders
+// every visible TreeItem regardless of their memo comparators.
+export default memo(Sidebar);
 
 function getGitContextMenuItems({
   items,

apps/yaak-client/components/WebsocketRequestPane.tsx

@@ -1,5 +1,5 @@
 import type { WebsocketRequest } from "@yaakapp-internal/models";
-import { patchModel } from "@yaakapp-internal/models";
+import { flushAllModelWrites, patchModel, patchModelDebounced } from "@yaakapp-internal/models";
 import type { GenericCompletionOption } from "@yaakapp-internal/plugins";
 import { closeWebsocket, connectWebsocket, sendWebsocket } from "@yaakapp-internal/ws";
 import classNames from "classnames";
@@ -8,8 +8,7 @@ import type { CSSProperties } from "react";
 import { useCallback, useMemo, useRef } from "react";
 import { getActiveCookieJar } from "../hooks/useActiveCookieJar";
 import { getActiveEnvironment } from "../hooks/useActiveEnvironment";
-import { activeRequestIdAtom } from "../hooks/useActiveRequestId";
-import { allRequestsAtom } from "../hooks/useAllRequests";
+import { allRequestUrlsAtom } from "../hooks/useAllRequests";
 import { useAuthTab } from "../hooks/useAuthTab";
 import { useCancelHttpResponse } from "../hooks/useCancelHttpResponse";
 import { useHeadersTab } from "../hooks/useHeadersTab";
@@ -18,7 +17,6 @@ import { usePinnedHttpResponse } from "../hooks/usePinnedHttpResponse";
 import { activeWebsocketConnectionAtom } from "../hooks/usePinnedWebsocketConnection";
 import { useRequestEditor, useRequestEditorEvent } from "../hooks/useRequestEditor";
 import { useRequestUpdateKey } from "../hooks/useRequestUpdateKey";
-import { deepEqualAtom } from "../lib/atoms";
 import { languageFromContentType } from "../lib/contentType";
 import { generateId } from "../lib/generateId";
 import { extractPathPlaceholders } from "../lib/pathPlaceholders";
@@ -55,15 +53,12 @@ const TAB_SETTINGS = "settings";
 const TAB_DESCRIPTION = "description";
 const TABS_STORAGE_KEY = "websocket_request_tabs";
 
-const nonActiveRequestUrlsAtom = atom((get) => {
-  const activeRequestId = get(activeRequestIdAtom);
-  const requests = get(allRequestsAtom);
-  return requests
-    .filter((r) => r.id !== activeRequestId)
-    .map((r): GenericCompletionOption => ({ type: "constant", label: r.url }));
-});
-
-const memoNotActiveRequestUrlsAtom = deepEqualAtom(nonActiveRequestUrlsAtom);
+// Derived from the identity-stable URL list so this only recomputes when a URL
+// actually changes. The active request's own URL is included, but exact matches
+// are filtered out at completion time by genericCompletion.
+const requestUrlOptionsAtom = atom((get): GenericCompletionOption[] =>
+  get(allRequestUrlsAtom).map((url) => ({ type: "constant", label: url })),
+);
 
 export function WebsocketRequestPane({ style, fullHeight, className, activeRequest }: Props) {
   const activeRequestId = activeRequest.id;
@@ -128,7 +123,7 @@ export function WebsocketRequestPane({ style, fullHeight, className, activeReque
   const { mutate: cancelResponse } = useCancelHttpResponse(activeResponse?.id ?? null);
   const connection = useAtomValue(activeWebsocketConnectionAtom);
 
-  const autocompleteUrls = useAtomValue(memoNotActiveRequestUrlsAtom);
+  const autocompleteUrls = useAtomValue(requestUrlOptionsAtom);
 
   const autocomplete: GenericCompletionConfig = useMemo(
     () => getUrlCompletionConfig(autocompleteUrls),
@@ -136,6 +131,7 @@ export function WebsocketRequestPane({ style, fullHeight, className, activeReque
   );
 
   const handleConnect = useCallback(async () => {
+    await flushAllModelWrites(); // The backend reads the request from the DB
     await connectWebsocket({
       requestId: activeRequest.id,
       environmentId: getActiveEnvironment()?.id ?? null,
@@ -145,6 +141,7 @@ export function WebsocketRequestPane({ style, fullHeight, className, activeReque
 
   const handleSend = useCallback(async () => {
     if (connection == null) return;
+    await flushAllModelWrites(); // The backend reads the message from the DB
     await sendWebsocket({
       connectionId: connection?.id,
       environmentId: getActiveEnvironment()?.id ?? null,
@@ -157,7 +154,7 @@ export function WebsocketRequestPane({ style, fullHeight, className, activeReque
   }, [connection]);
 
   const handleUrlChange = useCallback(
-    (url: string) => patchModel(activeRequest, { url }),
+    (url: string) => patchModelDebounced(activeRequest, { url }),
     [activeRequest],
   );
 
@@ -241,7 +238,7 @@ export function WebsocketRequestPane({ style, fullHeight, className, activeReque
                 forceUpdateKey={forceUpdateKey}
                 headers={activeRequest.headers}
                 stateKey={`headers.${activeRequest.id}`}
-                onChange={(headers) => patchModel(activeRequest, { headers })}
+                onChange={(headers) => patchModelDebounced(activeRequest, { headers })}
               />
             </TabContent>
             <TabContent value={TAB_PARAMS}>
@@ -249,7 +246,7 @@ export function WebsocketRequestPane({ style, fullHeight, className, activeReque
                 stateKey={`params.${activeRequest.id}`}
                 forceUpdateKey={forceUpdateKey + urlParametersKey}
                 pairs={urlParameterPairs}
-                onChange={(urlParameters) => patchModel(activeRequest, { urlParameters })}
+                onChange={(urlParameters) => patchModelDebounced(activeRequest, { urlParameters })}
               />
             </TabContent>
             <TabContent value={TAB_MESSAGE}>
@@ -261,7 +258,7 @@ export function WebsocketRequestPane({ style, fullHeight, className, activeReque
                 heightMode={fullHeight ? "full" : "auto"}
                 defaultValue={activeRequest.message}
                 language={messageLanguage}
-                onChange={(message) => patchModel(activeRequest, { message })}
+                onChange={(message) => patchModelDebounced(activeRequest, { message })}
                 stateKey={`json.${activeRequest.id}`}
               />
             </TabContent>
@@ -278,7 +275,7 @@ export function WebsocketRequestPane({ style, fullHeight, className, activeReque
                   className="font-sans text-xl! px-0!"
                   containerClassName="border-0"
                   placeholder={resolvedModelName(activeRequest)}
-                  onChange={(name) => patchModel(activeRequest, { name })}
+                  onChange={(name) => patchModelDebounced(activeRequest, { name })}
                 />
                 <MarkdownEditor
                   name="request-description"
@@ -286,7 +283,7 @@ export function WebsocketRequestPane({ style, fullHeight, className, activeReque
                   defaultValue={activeRequest.description}
                   stateKey={`description.${activeRequest.id}`}
                   forceUpdateKey={forceUpdateKey}
-                  onChange={(description) => patchModel(activeRequest, { description })}
+                  onChange={(description) => patchModelDebounced(activeRequest, { description })}
                 />
               </div>
             </TabContent>

apps/yaak-client/components/core/Editor/Editor.tsx

@@ -1,4 +1,5 @@
 import { startCompletion } from "@codemirror/autocomplete";
+import { debounce } from "@yaakapp-internal/lib";
 import { defaultKeymap, historyField, indentWithTab } from "@codemirror/commands";
 import { foldState, forceParsing } from "@codemirror/language";
 import type { EditorStateConfig, Extension } from "@codemirror/state";
@@ -381,6 +382,7 @@ function EditorInner({
   const initEditorRef = useCallback(
     function initEditorRef(container: HTMLDivElement | null) {
       if (container === null) {
+        flushCachedEditorState(stateKey);
         cm.current?.view.destroy();
         cm.current = null;
         return;
@@ -639,7 +641,7 @@ function getExtensions({
         onChange.current?.(update.state.doc.toString());
       }
 
-      saveCachedEditorState(stateKey, update.state);
+      saveCachedEditorStateDebounced(stateKey, update.state);
     }),
   ];
 }
@@ -652,6 +654,27 @@ const placeholderElFromText = (text: string | undefined) => {
   return el;
 };
 
+// Serializing the state (full doc + history) and md5-ing the doc is too
+// expensive to do on every update (each keystroke and cursor move), so
+// debounce it per state key and flush when the editor unmounts.
+const SAVE_STATE_DEBOUNCE_MS = 500;
+const stateSavers = new Map<string, ReturnType<typeof debounce>>();
+
+function saveCachedEditorStateDebounced(stateKey: string | null, state: EditorState) {
+  if (!stateKey) return;
+  let saver = stateSavers.get(stateKey);
+  if (saver == null) {
+    saver = debounce((s: EditorState) => saveCachedEditorState(stateKey, s), SAVE_STATE_DEBOUNCE_MS);
+    stateSavers.set(stateKey, saver);
+  }
+  saver(state);
+}
+
+function flushCachedEditorState(stateKey: string | null) {
+  if (!stateKey) return;
+  stateSavers.get(stateKey)?.flush();
+}
+
 function saveCachedEditorState(stateKey: string | null, state: EditorState | null) {
   if (!stateKey || state == null) return;
   const stateObj = state.toJSON(stateFields);

apps/yaak-client/hooks/useAllRequests.ts

@@ -4,6 +4,7 @@ import {
   websocketRequestsAtom,
 } from "@yaakapp-internal/models";
 import { atom, useAtomValue } from "jotai";
+import { selectAtom } from "jotai/utils";
 
 export const allRequestsAtom = atom((get) => [
   ...get(httpRequestsAtom),
@@ -14,3 +15,26 @@ export const allRequestsAtom = atom((get) => [
 export function useAllRequests() {
   return useAtomValue(allRequestsAtom);
 }
+
+const stringArrayEqual = (a: string[], b: string[]) =>
+  a.length === b.length && a.every((v, i) => v === b[i]);
+
+// Identity-stable derivations so subscribers don't recompute or re-render when
+// unrelated request fields change (eg. every debounced edit of a request)
+export const allRequestIdsAtom = selectAtom(
+  allRequestsAtom,
+  (requests) => requests.map((r) => r.id),
+  stringArrayEqual,
+);
+
+export const allRequestUrlsAtom = selectAtom(
+  allRequestsAtom,
+  (requests) => {
+    const urls = new Set<string>();
+    for (const r of requests) {
+      if (r.url) urls.add(r.url);
+    }
+    return Array.from(urls);
+  },
+  stringArrayEqual,
+);

apps/yaak-client/hooks/useGrpc.ts

@@ -1,6 +1,7 @@
 import { useMutation, useQuery } from "@tanstack/react-query";
 import { emit } from "@tauri-apps/api/event";
 import type { GrpcConnection, GrpcRequest } from "@yaakapp-internal/models";
+import { flushAllModelWrites } from "@yaakapp-internal/models";
 import { jotaiStore } from "../lib/jotai";
 import { minPromiseMillis } from "../lib/minPromiseMillis";
 import { invokeCmd } from "../lib/tauri";
@@ -22,8 +23,14 @@ export function useGrpc(
 
   const go = useMutation<void, string>({
     mutationKey: ["grpc_go", conn?.id],
-    mutationFn: () =>
-      invokeCmd<void>("cmd_grpc_go", { requestId, environmentId: environment?.id, protoFiles }),
+    mutationFn: async () => {
+      await flushAllModelWrites(); // The backend reads the request from the DB
+      return invokeCmd<void>("cmd_grpc_go", {
+        requestId,
+        environmentId: environment?.id,
+        protoFiles,
+      });
+    },
   });
 
   const send = useMutation({

apps/yaak-client/hooks/useParentFolders.ts

@@ -6,21 +6,19 @@ import { useMemo } from "react";
 export function useParentFolders(m: Folder | HttpRequest | GrpcRequest | WebsocketRequest | null) {
   const folders = useAtomValue(foldersAtom);
 
-  return useMemo(() => getParentFolders(folders, m), [folders, m]);
+  // Key on folderId, not the model itself, so edits to the model (eg. every URL
+  // keystroke replacing the active request) don't produce a new array identity
+  const folderId = m?.folderId ?? null;
+  return useMemo(() => getParentFolders(folders, folderId), [folders, folderId]);
 }
 
-function getParentFolders(
-  folders: Folder[],
-  currentModel: Folder | HttpRequest | GrpcRequest | WebsocketRequest | null,
-): Folder[] {
-  if (currentModel == null) return [];
+function getParentFolders(folders: Folder[], folderId: string | null): Folder[] {
+  if (folderId == null) return [];
 
-  const parentFolder = currentModel.folderId
-    ? folders.find((f) => f.id === currentModel.folderId)
-    : null;
+  const parentFolder = folders.find((f) => f.id === folderId);
   if (parentFolder == null) {
     return [];
   }
 
-  return [parentFolder, ...getParentFolders(folders, parentFolder)];
+  return [parentFolder, ...getParentFolders(folders, parentFolder.folderId ?? null)];
 }

crates/yaak-models/guest-js/store.ts

@@ -1,5 +1,6 @@
 import { invoke } from "@tauri-apps/api/core";
 import { getCurrentWebviewWindow } from "@tauri-apps/api/webviewWindow";
+import { debounce } from "@yaakapp-internal/lib";
 import { AnyModel, ModelPayload } from "../bindings/gen_models";
 import { modelStoreDataAtom } from "./atoms";
 import { ExtractModel, JotaiStore, ModelStoreData } from "./types";
@@ -12,6 +13,9 @@ const pendingModelWrites = new Set<Promise<unknown>>();
 export function initModelStore(store: JotaiStore) {
   _store = store;
 
+  // Don't lose debounced patches if the window closes while one is pending
+  window.addEventListener("beforeunload", flushAllPendingPatches);
+
   getCurrentWebviewWindow()
     .listen<ModelPayload>("model_write", ({ payload }) => {
       if (shouldIgnoreModel(payload)) return;
@@ -53,6 +57,7 @@ function trackModelWrite<T>(write: Promise<T>): Promise<T> {
 }
 
 export async function flushAllModelWrites(): Promise<void> {
+  flushAllPendingPatches();
   const results = await Promise.allSettled(pendingModelWrites);
   const rejected = results.find((result) => result.status === "rejected");
   if (rejected?.status === "rejected") {
@@ -60,6 +65,61 @@ export async function flushAllModelWrites(): Promise<void> {
   }
 }
 
+const PATCH_DEBOUNCE_MS = 400;
+
+interface PendingPatch {
+  model: AnyModel["model"];
+  id: string;
+  patch: Record<string, unknown>;
+  write: ReturnType<typeof debounce>;
+}
+
+const pendingPatches = new Map<string, PendingPatch>();
+
+/**
+ * Like patchModel, but coalesces rapid patches to the same model (eg. one per
+ * keystroke) into a single write. Later fields overwrite earlier ones, so it's
+ * only safe for whole-value fields like url, body, or headers. Pending patches
+ * flush after a short delay, and flushAllModelWrites() (called before sends and
+ * duplicates) flushes them immediately.
+ */
+export function patchModelDebounced<
+  M extends AnyModel["model"],
+  T extends ExtractModel<AnyModel, M>,
+>(base: Pick<T, "id" | "model">, patch: Partial<T>): void {
+  const key = `${base.model}.${base.id}`;
+  let pending = pendingPatches.get(key);
+  if (pending == null) {
+    pending = {
+      model: base.model,
+      id: base.id,
+      patch: {},
+      write: debounce(() => writePendingPatch(key), PATCH_DEBOUNCE_MS),
+    };
+    pendingPatches.set(key, pending);
+  }
+  pending.patch = { ...pending.patch, ...patch };
+  pending.write();
+}
+
+function writePendingPatch(key: string) {
+  const pending = pendingPatches.get(key);
+  if (pending == null) return;
+  pendingPatches.delete(key);
+  try {
+    void patchModelById(pending.model, pending.id, pending.patch);
+  } catch (err) {
+    // Model may have been deleted while the patch was pending
+    console.warn("Failed to flush pending patch", key, err);
+  }
+}
+
+export function flushAllPendingPatches() {
+  for (const pending of Array.from(pendingPatches.values())) {
+    pending.write.flush();
+  }
+}
+
 let _activeWorkspaceId: string | null = null;
 
 export async function changeModelStoreWorkspace(workspaceId: string | null) {

packages/common-lib/debounce.ts

@@ -1,13 +1,32 @@
 // oxlint-disable-next-line no-explicit-any
 export function debounce(fn: (...args: any[]) => void, delay = 500) {
-  let timer: ReturnType<typeof setTimeout>;
+  let timer: ReturnType<typeof setTimeout> | null = null;
+  // oxlint-disable-next-line no-explicit-any
+  let lastArgs: any[] | null = null;
   // oxlint-disable-next-line no-explicit-any
   const result = (...args: any[]) => {
-    clearTimeout(timer);
-    timer = setTimeout(() => fn(...args), delay);
+    lastArgs = args;
+    if (timer != null) clearTimeout(timer);
+    timer = setTimeout(() => {
+      timer = null;
+      const argsToUse = lastArgs ?? [];
+      lastArgs = null;
+      fn(...argsToUse);
+    }, delay);
   };
   result.cancel = () => {
+    if (timer != null) clearTimeout(timer);
+    timer = null;
+    lastArgs = null;
+  };
+  // Invoke a pending call immediately instead of waiting out the delay
+  result.flush = () => {
+    if (timer == null) return;
     clearTimeout(timer);
+    timer = null;
+    const argsToUse = lastArgs ?? [];
+    lastArgs = null;
+    fn(...argsToUse);
   };
   return result;
 }

packages/ui/src/components/tree/Tree.tsx

@@ -1,4 +1,5 @@
 import type { DragEndEvent, DragMoveEvent, DragStartEvent } from "@dnd-kit/core";
+import type { Virtualizer } from "@tanstack/react-virtual";
 import {
   DndContext,
   MeasuringStrategy,
@@ -23,7 +24,7 @@ import {
 } from "react";
 import { useKey, useKeyPressEvent } from "react-use";
 import { computeSideForDragMove } from "../../lib/dnd";
-import { useStore } from "jotai";
+import { useAtomValue, useStore } from "jotai";
 import { draggingIdsFamily, focusIdsFamily, hoveredParentFamily, selectedIdsFamily } from "./atoms";
 import { type CollapsedAtom, CollapsedAtomContext } from "./context";
 import type { ContextMenuRenderer, JotaiStore, SelectableTreeNode, TreeNode } from "./common";
@@ -87,7 +88,27 @@ function TreeInner<T extends { id: string }>(
 ) {
   const store = useStore();
   const treeRef = useRef<HTMLDivElement>(null);
+  const virtualizerRef = useRef<Virtualizer<HTMLElement, Element> | null>(null);
+  const getScrollElement = useCallback(() => treeRef.current, []);
+  const handleVirtualizerReady = useCallback((v: Virtualizer<HTMLElement, Element>) => {
+    virtualizerRef.current = v;
+  }, []);
   const selectableItems = useSelectableItems(root);
+
+  // Only render nodes that are actually visible (not filtered out, and not
+  // inside a collapsed folder). Mounting every node regardless of visibility
+  // makes large workspaces unusable: thousands of hidden TreeItems each run
+  // their dnd/context hooks on every tree commit just to return null.
+  const collapsedMap = useAtomValue(collapsedAtom);
+  const visibleItems = useMemo(() => {
+    return selectableItems.filter((i) => {
+      if (i.node.hidden) return false;
+      for (let p = i.node.parent; p != null; p = p.parent) {
+        if (collapsedMap[p.item.id]) return false;
+      }
+      return true;
+    });
+  }, [selectableItems, collapsedMap]);
   const [showContextMenu, setShowContextMenu] = useState<{
     items: unknown[];
     x: number;
@@ -125,16 +146,28 @@ function TreeInner<T extends { id: string }>(
   }, []);
 
   const tryFocus = useCallback(() => {
-    const $el = treeRef.current?.querySelector<HTMLButtonElement>(
-      '.tree-item button[tabindex="0"]',
-    );
-    if ($el == null) {
+    const find = () =>
+      treeRef.current?.querySelector<HTMLButtonElement>('.tree-item button[tabindex="0"]');
+    const $el = find();
+    if ($el != null) {
+      // preventScroll so scrolling stays single-sourced (focus() implicitly
+      // scrolls, which fights the virtualizer's scrollToIndex)
+      $el.focus({ preventScroll: true });
+      $el.scrollIntoView({ block: "nearest" });
+      return true;
+    }
+
+    // The focused row may be virtualized out of range. Scroll it into range,
+    // then focus it once it has mounted.
+    const lastFocusedId = store.get(focusIdsFamily(treeId)).lastId;
+    const index = visibleItems.findIndex((i) => i.node.item.id === lastFocusedId);
+    if (index < 0) {
       return false;
     }
-    $el.focus();
-    $el.scrollIntoView({ block: "nearest" });
+    virtualizerRef.current?.scrollToIndex(index, { align: "auto" });
+    requestAnimationFrame(() => find()?.focus({ preventScroll: true }));
     return true;
-  }, []);
+  }, [store, treeId, visibleItems]);
 
   const ensureTabbableItem = useCallback(() => {
     const lastSelectedId = store.get(focusIdsFamily(treeId)).lastId;
@@ -448,8 +481,8 @@ function TreeInner<T extends { id: string }>(
         store.set(hoveredParentFamily(treeId), {
           parentId: root.item.id,
           parentDepth: root.depth,
-          index: selectableItems.length,
-          childIndex: selectableItems.length,
+          index: visibleItems.length,
+          childIndex: visibleItems.length,
         });
         return;
       }
@@ -477,8 +510,8 @@ function TreeInner<T extends { id: string }>(
 
       const item = node.item;
       let hoveredParent = node.parent;
-      const dragIndex = selectableItems.findIndex((n) => n.node.item.id === item.id) ?? -1;
-      const hovered = selectableItems[dragIndex]?.node ?? null;
+      const dragIndex = visibleItems.findIndex((n) => n.node.item.id === item.id) ?? -1;
+      const hovered = visibleItems[dragIndex]?.node ?? null;
       const hoveredIndex = dragIndex + (side === "before" ? 0 : 1);
       let hoveredChildIndex = overSelectableItem.index + (side === "before" ? 0 : 1);
 
@@ -509,7 +542,7 @@ function TreeInner<T extends { id: string }>(
         });
       }
     },
-    [root.depth, root.item.id, selectableItems, treeId],
+    [root.depth, root.item.id, selectableItems, treeId, visibleItems],
   );
 
   const handleDragStart = useCallback(
@@ -680,12 +713,18 @@ function TreeInner<T extends { id: string }>(
               "[&_.tree-item.selected+.drop-marker+.tree-item.selected]:rounded-t-none",
               "[&_.tree-item.selected:has(+.tree-item.selected)]:rounded-b-none",
               "[&_.tree-item.selected:has(+.drop-marker+.tree-item.selected)]:rounded-b-none",
+              // Virtualized rows are wrapped in .tree-row divs, so the sibling
+              // relationships above need wrapper-aware equivalents
+              "[&_.tree-row:has(.tree-item.selected)+.tree-row_.tree-item.selected]:rounded-t-none",
+              "[&_.tree-row:has(.tree-item.selected):has(+.tree-row_.tree-item.selected)_.tree-item.selected]:rounded-b-none",
             )}
           >
             <TreeItemList
               addTreeItemRef={handleAddTreeItemRef}
-              nodes={selectableItems}
+              nodes={visibleItems}
               treeId={treeId}
+              getScrollElement={getScrollElement}
+              onVirtualizerReady={handleVirtualizerReady}
               {...treeItemListProps}
             />
           </div>

packages/ui/src/components/tree/TreeItemList.tsx

@@ -1,5 +1,7 @@
+import type { Virtualizer } from "@tanstack/react-virtual";
+import { useVirtualizer } from "@tanstack/react-virtual";
 import type { CSSProperties } from "react";
-import { Fragment } from "react";
+import { Fragment, useLayoutEffect, useRef, useState } from "react";
 import type { SelectableTreeNode } from "./common";
 import type { TreeProps } from "./Tree";
 import { TreeDropMarker } from "./TreeDropMarker";
@@ -22,9 +24,22 @@ export type TreeItemListProps<T extends { id: string }> = Pick<
     className?: string;
     forceDepth?: number;
     addTreeItemRef?: (item: T, n: TreeItemHandle | null) => void;
+    /**
+     * Enable virtualization by providing the scroll container. Rows are then
+     * windowed with @tanstack/react-virtual and only visible rows mount.
+     */
+    getScrollElement?: () => HTMLElement | null;
+    onVirtualizerReady?: (v: Virtualizer<HTMLElement, Element>) => void;
   };
 
-export function TreeItemList<T extends { id: string }>({
+export function TreeItemList<T extends { id: string }>(props: TreeItemListProps<T>) {
+  if (props.getScrollElement != null) {
+    return <VirtualTreeItemList {...props} getScrollElement={props.getScrollElement} />;
+  }
+  return <StaticTreeItemList {...props} />;
+}
+
+function StaticTreeItemList<T extends { id: string }>({
   className,
   getItemKey,
   nodes,
@@ -32,6 +47,8 @@ export function TreeItemList<T extends { id: string }>({
   treeId,
   forceDepth,
   addTreeItemRef,
+  getScrollElement: _getScrollElement,
+  onVirtualizerReady: _onVirtualizerReady,
   ...props
 }: TreeItemListProps<T>) {
   return (
@@ -53,3 +70,89 @@ export function TreeItemList<T extends { id: string }>({
     </ul>
   );
 }
+
+// Rows are --height-sm (2rem). Derive the pixel estimate from the actual root
+// font size so scroll math stays accurate under interface scaling.
+function estimateRowHeightPx() {
+  const rem = Number.parseFloat(getComputedStyle(document.documentElement).fontSize) || 16;
+  return 2 * rem;
+}
+
+function VirtualTreeItemList<T extends { id: string }>({
+  className,
+  getItemKey,
+  nodes,
+  style,
+  treeId,
+  forceDepth,
+  addTreeItemRef,
+  getScrollElement,
+  onVirtualizerReady,
+  ...props
+}: TreeItemListProps<T> & { getScrollElement: () => HTMLElement | null }) {
+  const listRef = useRef<HTMLUListElement>(null);
+
+  // Offset of the list within the scroll container (eg. container padding),
+  // so windowing and scrollToIndex targets aren't shifted by it
+  const [scrollMargin, setScrollMargin] = useState(0);
+  useLayoutEffect(() => {
+    const list = listRef.current;
+    const scroller = getScrollElement();
+    if (list == null || scroller == null) return;
+    const offset =
+      list.getBoundingClientRect().top - scroller.getBoundingClientRect().top + scroller.scrollTop;
+    setScrollMargin(offset);
+  }, [getScrollElement]);
+
+  const virtualizer = useVirtualizer({
+    count: nodes.length,
+    getScrollElement,
+    estimateSize: estimateRowHeightPx,
+    overscan: 10,
+    scrollMargin,
+  });
+
+  useLayoutEffect(() => {
+    onVirtualizerReady?.(virtualizer);
+  }, [virtualizer, onVirtualizerReady]);
+
+  return (
+    <ul
+      ref={listRef}
+      style={{ ...style, height: `${virtualizer.getTotalSize()}px`, position: "relative" }}
+      className={className}
+    >
+      <TreeDropMarker node={null} treeId={treeId} index={0} />
+      {virtualizer.getVirtualItems().map((virtualItem) => {
+        const child = nodes[virtualItem.index];
+        if (child == null) return null;
+        return (
+          <div
+            // Key by item so window shifts don't remount rows unnecessarily
+            key={getItemKey(child.node.item)}
+            ref={virtualizer.measureElement}
+            data-index={virtualItem.index}
+            className="tree-row"
+            style={{
+              position: "absolute",
+              top: 0,
+              left: 0,
+              width: "100%",
+              transform: `translateY(${virtualItem.start - scrollMargin}px)`,
+            }}
+          >
+            <TreeItem
+              treeId={treeId}
+              setRef={addTreeItemRef}
+              node={child.node}
+              getItemKey={getItemKey}
+              depth={forceDepth == null ? child.depth : forceDepth}
+              {...props}
+            />
+            <TreeDropMarker node={child.node} treeId={treeId} index={virtualItem.index + 1} />
+          </div>
+        );
+      })}
+    </ul>
+  );
+}