Heroku NodeJs doesn't upload modules to node_modules folder, what should I do?

Question

JavaScript

Need help.
I've googled this question a million times and can't find it anywhere.
I use heroku as a free server. I use for NodeJs.
The local version is 6.11.2.
When I try to start a project on heroku (remote), it says that a lot of modules are not installed. I checked the folder through bash. Indeed, the folder is empty.
But! The package.json specifies that express and one more module should be included.
As a result, the modules are not included, the error remains. What to do?
Thanks