🔨 build: Upgrade build script.

Author: make-github-pseudonymous-again

package.json

@@ -135,7 +135,7 @@
  "type": "git"
  },
  "scripts": {
- "build": "rm -rf lib && babel src -d lib",
+ "build": "babel --delete-dir-on-start --env-name production src -d lib",
  "cover": "nyc --reporter=lcov npm test",
  "esdoc": "esdoc",
  "prepare": "npm run build",