fix(browser): log ErrorEvent.message when unhandled ErrorEvent.error is null

packages/browser/src/client/public/error-catcher.js

@@ -31,7 +31,11 @@ function catchWindowErrors(errorEvent, prop, cb) {
       cb(e)
     }
     else {
-      console.error(e[prop])
+      // `ErrorEvent` doesn't necessary have `ErrotEvent.error` defined
+      // but some has `ErrorEvent.message` defined, e.g. ResizeObserver error.
+      // https://developer.mozilla.org/en-US/docs/Web/API/ErrorEvent/error
+      // https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver#observation_errors
+      console.error(e.message ? new Error(e.message) : e)
     }
   }
   const addEventListener = window.addEventListener.bind(window)

test/browser/fixtures/unhandled-non-error/basic.test.ts

@@ -0,0 +1,24 @@
+import { test } from "vitest";
+
+test("ResizeObserver error", async () => {
+	const divElem = document.createElement("div");
+	divElem.style.width = "100px";
+	divElem.style.height = "100px";
+	document.body.appendChild(divElem);
+
+	const resizeObserver = new ResizeObserver((entries) => {
+		for (const entry of entries) {
+			(entry.target as HTMLElement).style.width =
+				`${entry.contentBoxSize[0].inlineSize + 10}px`;
+		}
+	});
+	const promise = Promise.withResolvers();
+	window.addEventListener("error", (event) => {
+		if (event.message.includes("ResizeObserver loop")) {
+			promise.resolve(null);
+		}
+	});
+	resizeObserver.observe(divElem);
+	await promise.promise;
+	resizeObserver.unobserve(divElem);
+});

test/browser/fixtures/unhandled-non-error/vitest.config.ts

@@ -0,0 +1,15 @@
+import { fileURLToPath } from 'node:url'
+import { defineConfig } from 'vitest/config'
+import { instances, provider } from '../../settings'
+
+export default defineConfig({
+  cacheDir: fileURLToPath(new URL("./node_modules/.vite", import.meta.url)),
+  test: {
+    browser: {
+      enabled: true,
+      provider,
+      instances,
+      headless: true,
+    },
+  },
+})

test/browser/settings.ts

@@ -20,7 +20,9 @@ const devInstances: BrowserInstanceOption[] = [
 const playwrightInstances: BrowserInstanceOption[] = [
   { browser: 'chromium' },
   { browser: 'firefox' },
-  { browser: 'webkit' },
+  // hard to setup playwright webkit on some machines (e.g. ArchLinux)
+  // this allows skipping it locally by BROWSER_NO_WEBKIT=true
+  ...(process.env.BROWSER_NO_WEBKIT ? [] : [{ browser: 'webkit' as const }]),
 ]
 
 const webdriverioInstances: BrowserInstanceOption[] = [

test/browser/specs/unhandled.test.ts

@@ -37,3 +37,17 @@ test('disables tracking', async () => {
   })
   expect(stderr).toBe('')
 })
+
+test('print unhandled non error', async () => {
+  const { testTree, stderr } = await runBrowserTests({
+    root: './fixtures/unhandled-non-error',
+  })
+  expect(stderr).toContain('[Error: ResizeObserver loop completed with undelivered notifications.]')
+  expect(testTree()).toMatchInlineSnapshot(`
+    {
+      "basic.test.ts": {
+        "ResizeObserver error": "passed",
+      },
+    }
+  `)
+})