Create-React-App build - "Uncaught SyntaxError: Unexpected token <"

just remove

"homepage": "your app url "

from package.json to fix it

Remove the "homepage": "app-url" from package.json. Absence of homepage in package.json will assume that it will be hosted at the server root, or you will serve the build with serve -s build.

And Yes, specifying homepage will be helpful when you are going to deploy the App in a sub-directory of the server root.

To host your app on the IIS with the name somedomain.net and your solution already has a Web API project.

1. You will map the solution folder with the main Web app i.e., somedomain.net
2. You will convert the Web API project to Application from IIS.
3. Then you will convert the build folder of React App to web App just like Web API
4. To make front-end App working specify the "homepage": "somedomain.net/React-Project/Client-App/build"

I ended up finding an answer here: https://github.com/facebook/create-react-app/issues/1812

I trimmed down the full solution from above, but I changed:

app.use(express.static('client/build'));
app.get("*", (req, res) => {
    res.sendFile(require('path')
        .resolve(__dirname, 'client', 'build', 'index.html'));
})

to:

const root = require('path').join(__dirname, 'client', 'build')
app.use(express.static(root));
app.get("*", (req, res) => {
    res.sendFile('index.html', { root });
})

It's definitely a bit strange to me that the first block didn't work. I assume it has something to do with the relative links in my React project since I do get an index.html file delivered to browser, despite getting the error. Maybe a completely static file would work with the first block, but I'd be interested to know if that's accurate.

Thanks this helped me a lot. Just wanting to add to this with an example from a Create-React-App project that had the same solution: I received the same error after deploying to heroku.

Uncaught SyntaxError: Unexpected token < after serve -s build

For me the problem was in the packages.json file. The "homepage" parameter i gave was incorrect. Changing this to the correct heroku URL solved the issue.

"homepage": "https://myapp.herokuapp.com/"

Hope this addition is helpful.