My Node.js app is failing with a build error related to Yarn.
Heroku supports Yarn for installing Node.js dependencies - https://devcenter.heroku.com/changelog-items/1065
The build system checks for the presence of a
yarn.lock file in the repo. If you don't want to use Yarn on Heroku, we recommend adding
yarn.lock to your
.slugignore file https://devcenter.heroku.com/articles/slug-compiler#ignoring-files-with-slugignore