Migrate to vitest

.claude/agents/engineer.md

@@ -146,7 +146,7 @@ Modified files: [list from Step 2]
 Run these checks:
 
 1. `npm run build` (builds all packages in dependency order via tsc + esbuild)
-2. `npm test` (runs Jest tests across all packages)
+2. `npm test` (runs Vitest tests across all packages)
 3. `npm run lint` (ESLint + Prettier check)
 
 For single-package changes, you may scope:

.claude/agents/pr-reviewer.md

@@ -67,7 +67,7 @@ Run the full build and test suite:
 # Build all packages (tsc + esbuild, respects dependency order)
 npm run build
 
-# Run all tests (Jest across all packages)
+# Run all tests (Vitest across all packages)
 npm test
 
 # Lint check (ESLint + Prettier)

.devcontainer/devcontainer.json

@@ -2,16 +2,14 @@
   "name": "Exceptionless.JavaScript",
   "image": "mcr.microsoft.com/vscode/devcontainers/typescript-node:latest",
   "extensions": [
-    "andys8.jest-snippets",
     "dbaeumer.vscode-eslint",
     "editorconfig.editorconfig",
     "esbenp.prettier-vscode",
-    "firsttris.vscode-jest-runner",
-    "hbenl.vscode-test-explorer",
     "juancasanova.awesometypescriptproblemmatcher",
     "ryanluker.vscode-coverage-gutters",
-    "streetsidesoftware.code-spell-checker"
+    "streetsidesoftware.code-spell-checker",
+    "vitest.explorer"
   ],
   "forwardPorts": [3000],
-  "postCreateCommand": "npm install"
+  "postCreateCommand": "npm ci"
 }

.vscode/extensions.json

@@ -1,14 +1,12 @@
 {
   "recommendations": [
-    "andys8.jest-snippets",
     "davidanson.vscode-markdownlint",
     "dbaeumer.vscode-eslint",
     "editorconfig.editorconfig",
     "esbenp.prettier-vscode",
-    "firsttris.vscode-jest-runner",
-    "hbenl.vscode-test-explorer",
     "juancasanova.awesometypescriptproblemmatcher",
     "ryanluker.vscode-coverage-gutters",
-    "streetsidesoftware.code-spell-checker"
+    "streetsidesoftware.code-spell-checker",
+    "vitest.explorer"
   ]
 }

.vscode/launch.json

@@ -14,27 +14,27 @@
       "name": "Test",
       "request": "launch",
       "type": "node",
-      "program": "${workspaceFolder}/node_modules/.bin/jest",
-      "args": ["--runInBand"],
+      "program": "${workspaceFolder}/node_modules/.bin/vitest",
+      "args": ["--run"],
       "console": "integratedTerminal",
       "internalConsoleOptions": "neverOpen",
       "disableOptimisticBPs": true,
       "windows": {
-        "program": "${workspaceFolder}/node_modules/jest/bin/jest"
+        "program": "${workspaceFolder}/node_modules/vitest/vitest.mjs"
       },
       "cwd": "${workspaceRoot}"
     },
     {
       "name": "Test Current File",
       "request": "launch",
       "type": "node",
-      "program": "${workspaceFolder}/node_modules/.bin/jest",
-      "args": ["${fileBasenameNoExtension}"],
+      "program": "${workspaceFolder}/node_modules/.bin/vitest",
+      "args": ["--run", "${fileBasenameNoExtension}"],
       "console": "integratedTerminal",
       "internalConsoleOptions": "neverOpen",
       "disableOptimisticBPs": true,
       "windows": {
-        "program": "${workspaceFolder}/node_modules/jest/bin/jest"
+        "program": "${workspaceFolder}/node_modules/vitest/vitest.mjs"
       },
       "cwd": "${workspaceRoot}"
     }

.vscode/settings.json

@@ -36,6 +36,5 @@
     "webcompat"
   ],
   "eslint.validate": ["javascript", "typescript"],
-  "deno.enable": false,
-  "jest.jestCommandLine": "npm test --"
+  "deno.enable": false
 }

AGENTS.md

@@ -262,10 +262,10 @@ Before marking work complete, verify:
 
 ### Framework
 
-- **Jest** with **ts-jest** preset
-- **`@jest/globals`** for imports (`describe`, `test`, `expect`)
+- **Vitest** as the test runner
+- **`vitest`** for imports (`describe`, `test`, `expect`, `beforeEach`, `afterEach`)
 - **jsdom** test environment for browser packages, **node** for the node package
-- **jest-ts-webcompat-resolver** for ESM import resolution
+- **vitest.config.ts** at root defines test projects for each package
 
 ### Test Structure
 
@@ -288,8 +288,7 @@ packages/core/test/
 Follow the Arrange-Act-Assert pattern:
 
 ```typescript
-import { describe, test } from "@jest/globals";
-import { expect } from "expect";
+import { describe, test, expect } from "vitest";
 
 import { ExceptionlessClient } from "../src/ExceptionlessClient.js";
 
@@ -330,7 +329,7 @@ npm test --workspace=packages/browser
 npm run test:watch --workspace=packages/core
 
 # Run tests matching a pattern
-npx jest --testPathPattern="ExceptionlessClient"
+npx vitest --run --testNamePattern="ExceptionlessClient"
 ```
 
 ### Test Principles (FIRST)

eslint.config.mjs

@@ -1,13 +1,11 @@
 import eslint from "@eslint/js";
 import { defineConfig } from "eslint/config";
 import eslintConfigPrettier from "eslint-config-prettier";
-import jest from "eslint-plugin-jest";
+import vitest from "@vitest/eslint-plugin";
 import tseslint from "typescript-eslint";
 
 export default defineConfig(
-  {
-    ignores: ["**/dist/", "**/node_modules/", ".agents/", "example/", "jest-resolver.cjs"]
-  },
+  { ignores: ["**/dist/", "**/node_modules/", ".agents/", "example/"] },
   eslint.configs.recommended,
   {
     extends: tseslint.configs.recommendedTypeChecked,
@@ -36,12 +34,12 @@ export default defineConfig(
   eslintConfigPrettier,
   {
     files: ["**/test/**/*.ts"],
-    extends: [jest.configs["flat/recommended"]],
+    plugins: vitest.configs.recommended.plugins,
     rules: {
-      "jest/valid-title": "off",
-      "jest/valid-describe-callback": "off",
-      "jest/no-export": "off",
-      "jest/no-done-callback": "warn"
+      ...vitest.configs.recommended.rules,
+      "vitest/valid-title": "off",
+      "vitest/valid-describe-callback": "off",
+      "vitest/no-done-callback": "warn"
     }
   }
 );

example/react/package.json

@@ -9,8 +9,7 @@
   },
   "eslintConfig": {
     "extends": [
-      "react-app",
-      "react-app/jest"
+      "react-app"
     ]
   },
   "browserslist": {
@@ -26,7 +25,6 @@
     ]
   },
   "devDependencies": {
-    "@testing-library/jest-dom": "^6.9.1",
     "@testing-library/react": "^16.3.2",
     "@testing-library/user-event": "^14.6.1",
     "@vitejs/plugin-react": "^6.0.1",