Init Jest

jest.config.js

@@ -0,0 +1,5 @@
+/** @type {import('ts-jest').JestConfigWithTsJest} */
+export default {
+  preset: "ts-jest/presets/default-esm",
+  testEnvironment: "node",
+};

package.json

@@ -1,12 +1,16 @@
 {
+  "type": "module",
   "scripts": {
     "check": "tsc --noEmit",
     "serve": "esbuild src/3x5.ts --bundle --format=iife --outfile=bundle.js --sourcemap --servedir=.",
-    "build": "esbuild src/3x5.ts --bundle --format=iife --outfile=bundle.js"
+    "build": "esbuild src/3x5.ts --bundle --format=iife --outfile=bundle.js",
+    "test": "node --experimental-vm-modules ./node_modules/.bin/jest"
   },
   "devDependencies": {
+    "@types/jest": "^29.5.3",
     "esbuild": "^0.18.17",
     "jest": "^29.6.2",
+    "ts-jest": "^29.1.1",
     "typescript": "^5.1.6"
   }
 }