Issue
My Node.js app is failing with a build error related to Yarn.
Resolution
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