Heroku deploy sub-directory

Going through a couple of Udemy courses, and figured it was nice to keep all the code I wrote while doing them in a single github repository.

Was working nicely until I started the Node with React where part of the course is to deploy the app to Heroku which wants a full repository pushed to a certain git repo it creates for deployment. But in my case the app I want to deploy is of course a sub-directory…

Turns out there’s a git command called subtree one can use here:

# Setup
heroku login
heroku create

git remote add heroku/some-name https://git.heroku.com/{created-heroku-app-id}.git

# Deploy
git subtree push --force --prefix path/to/app heroku/some-name master

The subtree command needs to be run from the top-level directory of the git repository, but one can add a script command to the apps package.json, for example like this:

  "scripts": {
    "deploy": "cd ../../.. && git subtree push --prefix path/to/app heroku/some-name master"

Unfortunately, subtree push doesn’t support --force, but a workaround for that is running it nested like this:

git push heroku/some-name `git subtree split --prefix path/to/app master`:master --force

Which unfortunately doesn’t work on Windows… but you can do it in two steps instead:

git subtree split --prefix path/to/app master
git push heroku/some-name {id-from-previous-command}:master --force