add typechecking script

Author: chaance

package.json

@@ -15,6 +15,7 @@
     "build": "tsup",
     "format": "prettier --write .",
     "format:check": "prettier --check .",
+    "typecheck": "tsc --noEmit",
     "test": "echo \"Error: no test specified\" && exit 1"
   },
   "repository": {