What's the point of the dev-dependencies section?

Question

npm

I don't understand everything. What is the difference between normal dependencies and dev-dependencies?
It is clear that one is for development, and the other is for production. But when does it start to make sense? Those. in some cases the project is deployed ignoring dev-dependencies? I probably don't understand the project deployment process itself.

Answer 1

If you install the package directly, the dependencies from dev-dependencies will be installed. If you install a package as a dependency, then these packages will not be installed.
Here, in principle, it is written https://docs.npmjs.com/files/package.json#dependencies