Replace jest with vitest

.github/workflows/ci.yml

@@ -69,5 +69,8 @@ jobs:
       - name: Setup node
         uses: ./.github/actions/setup-node
 
+      - name: Install playwright dependencies
+        run: yarn playwright install --with-deps chromium
+
       - name: Run test
         run: yarn test

.gitignore

@@ -33,3 +33,7 @@ tsconfig*.tsbuildinfo
 npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
+
+# Vitest browser test attachments (screenshots, traces)
+.vitest-attachments
+**/__screenshots__

.oxlintrc.json

@@ -2,5 +2,16 @@
   "plugins": ["eslint", "import", "oxc", "react", "typescript"],
   "categories": {
     "correctness": "error"
+  },
+  "rules": {
+    "eslint/no-unused-vars": [
+      "error",
+      {
+        "caughtErrors": "none",
+        "argsIgnorePattern": "^_",
+        "varsIgnorePattern": "^_",
+        "destructuredArrayIgnorePattern": "^_"
+      }
+    ]
   }
 }

package.json

@@ -45,8 +45,8 @@
     "lint": "yarn oxlint",
     "precommit": "lint-staged",
     "publish": "yarn build && yarn npm publish",
-    "test": "jest --ci",
-    "test:watch": "yarn test --watch",
+    "test": "vitest run",
+    "test:watch": "vitest",
     "types": "tsc --noEmit"
   },
   "peerDependencies": {
@@ -59,20 +59,18 @@
   },
   "devDependencies": {
     "@arethetypeswrong/core": "^0.18.2",
-    "@types/jest": "^30.0.0",
     "@types/node": "^24.0.0",
     "@types/react": "^19.0.0",
-    "jest": "^30.3.0",
-    "jest-environment-jsdom": "^30.3.0",
-    "jest-watch-typeahead": "^3.0.1",
+    "@vitest/browser-playwright": "^4.1.5",
     "lint-staged": "^16.4.0",
     "oxfmt": "^0.38.0",
     "oxlint": "^1.53.0",
     "oxlint-tsgolint": "^0.16.0",
+    "playwright": "^1.49.0",
     "publint": "^0.3.18",
-    "ts-jest": "^29.4.9",
     "tsdown": "^0.21.10",
     "typescript": "^6.0.2",
-    "unplugin-unused": "^0.5.7"
+    "unplugin-unused": "^0.5.7",
+    "vitest": "^4.1.5"
   }
 }

src/client/__tests__/initialize.test.ts

@@ -7,12 +7,12 @@ describe('initialize', () => {
   beforeAll(() => {
     originalAddEventListener = window.addEventListener;
     originalRemoveEventListener = window.removeEventListener;
-    window.addEventListener = jest.fn();
-    window.removeEventListener = jest.fn();
+    window.addEventListener = vi.fn();
+    window.removeEventListener = vi.fn();
   });
 
   beforeEach(() => {
-    jest.resetAllMocks();
+    vi.resetAllMocks();
   });
 
   it('should initialize and be destroyable', () => {

src/client/initialize.ts

@@ -23,10 +23,20 @@ export function initialize<T = {}>(): PluginInstance<T> {
     [event: string]: Function[];
   } = {};
 
-  for (const [key, value] of new URL(
-    document.location.toString(),
-  ).searchParams.entries())
-    pluginConfig[key] = JSON.parse(value);
+  const location = new URL(document.location.href);
+  for (const [key, value] of location.searchParams.entries()) {
+    try {
+      pluginConfig[key] = JSON.parse(value);
+    } catch (_err: unknown) {
+      if (__VITEST_BROWSER__ && (key === 'frameId' || key === 'sessionId')) {
+        // noop: vitest browser injects these into the test iframe URL
+      } else {
+        console.error(
+          `Failed to parse URL param ${key} with value ${value} as JSON.`,
+        );
+      }
+    }
+  }
 
   const listener = (e: PluginMessageResponse) => {
     emit(e.data.type, e.data.result, e.data.error);

src/globals.d.ts

@@ -1 +1,2 @@
 declare const __VERSION__: string;
+declare const __VITEST_BROWSER__: boolean;

tsconfig.json

@@ -14,7 +14,7 @@
     "esModuleInterop": true,
     "forceConsistentCasingInFileNames": true,
     "skipLibCheck": true,
-    "types": ["jest"]
+    "types": ["vitest/globals"]
   },
-  "include": ["src", "jest.config.ts", "tsdown.config.ts"]
+  "include": ["src", "vitest.config.ts", "tsdown.config.ts"]
 }

tsdown.config.ts

@@ -26,6 +26,7 @@ export default defineConfig({
 
   define: {
     __VERSION__: JSON.stringify(packageJson.version),
+    __VITEST_BROWSER__: false.toString(),
   },
 
   publint: true,

vitest.config.ts

@@ -0,0 +1,21 @@
+import { playwright } from '@vitest/browser-playwright';
+import { defineConfig } from 'vitest/config';
+
+import packageJson from './package.json' with { type: 'json' };
+
+export default defineConfig({
+  define: {
+    __VERSION__: JSON.stringify(packageJson.version),
+    __VITEST_BROWSER__: true.toString(),
+  },
+  test: {
+    globals: true,
+    include: ['src/**/*.test.{js,jsx,ts,tsx}'],
+    browser: {
+      enabled: true,
+      provider: playwright(),
+      headless: true,
+      instances: [{ browser: 'chromium' }],
+    },
+  },
+});