Step 1: Create a Procfile with the following line: web: npm run start:prod. We are doing this because heroku runs npm run start by default, so we need this setting to override the default run command.
Step 2: Install heroku's buildpack on your heroku app by running the following command: heroku buildpacks:set https://github.com/heroku/heroku-buildpack-nodejs#v90 -a [your app name]. Make sure to replace #v90 with whatever the latest buildpack is which you can find here.
Step 3: Add this line to your Package.json file in the scripts area: "postinstall": "npm run build:clean",. This is because Heroku runs this as part of their build process (more of which you can read about here).
Step 4: Run heroku config:set NPM_CONFIG_PRODUCTION=false so that Heroku can compile the NPM Modules included in your devDependencies (since many of these packages are required for the build process).
Step 5: Follow the standard Heroku deploy process at this point:
git add .git commit -m 'Made some epic changes as per usual'git push heroku master