Build package as ESM

Author: blakeembrey

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       matrix:
         node-version:
-          - "18"
+          - "20"
           - "*"
     steps:
       - uses: actions/checkout@v4

package.json

@@ -17,6 +17,8 @@
     "url": "https://opencollective.com/express"
   },
   "license": "MIT",
+  "sideEffects": false,
+  "type": "module",
   "exports": "./dist/index.js",
   "main": "dist/index.js",
   "typings": "dist/index.d.ts",
@@ -45,15 +47,15 @@
     "vitest": "^3.0.5"
   },
   "engines": {
-    "node": ">=18"
+    "node": ">=20"
   },
   "publishConfig": {
     "access": "public"
   },
   "size-limit": [
     {
       "path": "dist/index.js",
-      "limit": "2 kB"
+      "limit": "1.85 kB"
     }
   ],
   "ts-scripts": {