perf: faster app startup

src/cm/keyBindingUtils.js

@@ -45,8 +45,10 @@ export function toCodeMirrorKey(combo) {
 	return strokes.length ? strokes.join(" ") : null;
 }
 
-// Conflict checks compare every binding with every other one each time the
-// keymap is rebuilt (once per registered command), so cache the parsed form.
+// Conflict checks compare every binding with every other one on each keymap
+// rebuild, so cache the parsed form. The app has a few hundred binding strings;
+// the cap only stops unbounded growth from repeated registrations of new keys.
+const MAX_CANONICAL_KEY_CACHE_SIZE = 1000;
 const canonicalKeyCache = new Map();
 
 export function canonicalizeKeyBinding(combo) {
@@ -55,6 +57,9 @@ export function canonicalizeKeyBinding(combo) {
 	}
 	if (canonicalKeyCache.has(combo)) return canonicalKeyCache.get(combo);
 	const canonicalKey = toCodeMirrorKey(combo)?.toLowerCase() || null;
+	if (canonicalKeyCache.size >= MAX_CANONICAL_KEY_CACHE_SIZE) {
+		canonicalKeyCache.clear();
+	}
 	canonicalKeyCache.set(combo, canonicalKey);
 	return canonicalKey;
 }

src/lib/run.js

@@ -30,14 +30,16 @@ const CONSOLE_THEME_STATE = "__acode_console_theme.json";
  * @param {Boolean} isConsole
  * @param {"inapp"|"browser"} target
  * @param {Boolean} runFile
+ * @param {EditorFile} [file] file to run, captured when the run was requested
  */
 async function run(
 	isConsole = false,
 	target = appSettings.value.previewMode,
 	runFile = false,
+	file = editorManager.activeFile,
 ) {
 	/** @type {EditorFile} */
-	const activeFile = isConsole ? null : editorManager.activeFile;
+	const activeFile = isConsole ? null : file;
 
 	if (!isConsole && Url.extname(activeFile?.filename || "") === ".md") {
 		if (!(await activeFile?.canRun())) return;

src/lib/runLazily.js

@@ -1,9 +1,14 @@
 /**
- * Runs/previews a file, loading the runner on first use. The runner pulls in
- * markdown-it and the markdown preview, which are not needed at startup.
- * @param {...any} args arguments for lib/run
+ * Runs/previews the active file, loading the runner on first use. The runner
+ * pulls in markdown-it and the markdown preview, which are not needed at
+ * startup.
+ * @param {boolean} [isConsole]
+ * @param {"inapp"|"browser"} [target]
+ * @param {boolean} [runFile]
  */
-export default async function runLazily(...args) {
+export default async function runLazily(isConsole, target, runFile) {
+	// Capture the file now: the user may switch tabs while the runner loads.
+	const file = isConsole ? null : editorManager.activeFile;
 	const { default: run } = await import(/* webpackChunkName: "run" */ "./run");
-	return run(...args);
+	return run(isConsole, target, runFile, file);
 }

tests/unit/runLazily.test.js

@@ -0,0 +1,34 @@
+import { expect, it, vi } from "vitest";
+import { loadSourceModule } from "../helpers/loadSourceModule";
+
+function setup() {
+	const run = vi.fn();
+	const editorManager = { activeFile: { id: "requested" } };
+	const { default: runLazily } = loadSourceModule(
+		"src/lib/runLazily.js",
+		{ "./run": { __esModule: true, default: run } },
+		{ editorManager },
+	);
+	return { run, editorManager, runLazily };
+}
+
+it("runs the file that was active when the run was requested", async () => {
+	const { run, editorManager, runLazily } = setup();
+
+	const pending = runLazily(false, "inapp", true);
+	// The user switches tabs while the runner chunk is still loading.
+	editorManager.activeFile = { id: "switched" };
+	await pending;
+
+	expect(run).toHaveBeenCalledExactlyOnceWith(false, "inapp", true, {
+		id: "requested",
+	});
+});
+
+it("does not capture a file for the console", async () => {
+	const { run, runLazily } = setup();
+
+	await runLazily(true, "inapp");
+
+	expect(run).toHaveBeenCalledExactlyOnceWith(true, "inapp", undefined, null);
+});