diff --git a/package.json b/package.json
index f05c406776..27ed3444c8 100644
--- a/package.json
+++ b/package.json
@@ -29,6 +29,7 @@
     "flow-bin": "^0.33.0",
     "lodash": "^4.15.0",
     "nyc": "^8.1.0",
+    "rimraf": "^2.5.4",
     "rollup": "^0.36.3",
     "rollup-plugin-babel": "^2.6.1",
     "rollup-plugin-node-resolve": "^2.0.0",
@@ -41,8 +42,9 @@
     "build": "rollup -c",
     "coverage": "nyc report --reporter=json && codecov -f coverage/coverage-final.json",
     "lint": "eslint src bin",
+    "clean": "rimraf lib",
     "flow": "flow",
-    "prepublish": "cross-env BABEL_ENV=production npm run build",
+    "prepublish": "npm run clean && cross-env BABEL_ENV=production npm run build",
     "preversion": "npm run test && npm run changelog",
     "test": "npm run lint && npm run flow && npm run build && npm run test-only",
     "test-only": "ava test",