The Node.js platform provides Heroku-specific build hooks

Change effective on 11 March 2016

Sometimes, developers need something more production-oriented than the preinstall and postinstall hooks in package.json. For instance, some apps need to set up extra authentication before installing dependencies. Some need to build assets, but not in a development environment. Further examples can be found in the discussion on GitHub.

Node.js developers can now use heroku-prebuild and heroku-postbuild hooks to tailor the build process to their apps.