How to add -a -app in my Websockets file?

Question

I've got a problem when I upload my project on Heroku. I've trying changing value of socket.io and MongoUrl, but I get this error:

Error: Missing required flag:
›     -a, --app APP  app to run command against

Answer 1

This has nothing to do with any of your files. It's an argument that you must provide to the Heroku CLI itself, e.g.

heroku config:set SOME_VARIABLE=some_value -a myapp

where myapp is the name of your Heroku app.

The -a / --app argument is required when heroku can't figure out what app to connect to, either bcause there is no Heroku remote configured or because there is more than one Heroku remote configured.

See also How to avoid the --app option with heroku CLI?