express - Create-React-App deployment to Heroku failed with ` react-scripts: not found`

Question

We're developing a ReactJS application using Create-React-App, that is served from our Node/Express server that also serves API's. We deploy the whole server to Heroku using node/JS buildpack and trying to get the CRA build step npm run build in postinstall script from the node package.json file as suggested by @mars in this issue.

The issue is that Heroku deployment is failing with this error. Note that this error happen to me sometime locally but then a npm install from the web_app is solving the issue, but not when run in Heroku. I have two related questions:

1. How to deploy to Heroku a Node/Express app that serves both APIs and a Create-React-App application? I can commit my build directory but this is really not the right way.
2. Why the react-scripts are disappearing and I have to run multiple times the npm install.

Answer 1

@johnnycon -

This was exactly the issue and I've received the answer from Mars in this github issue post:

@philjoseph, react-scripts is (by default) a devDependency for CRA apps, but Heroku Node buildpack has environment NODE_ENV=production which causes npm install to skip devDeps.

To install those devDeps too:

npm install --only=dev && npm install && npm run build

He also pointed to this excellent repo: https://github.com/mars/heroku-cra-node

I followed this and it works like a charm :)