What is the difference between --save and --save-dev?

Question

What is the difference between:

npm install [package_name]

and:

npm install [package_name] --save

and:

Answer 1

All explanations here are great, but lacking a very important thing: How do you install production dependencies only? (without the development dependencies). We separate dependencies from devDependencies by using --save or --save-dev. To install all we use:

npm i

To install only production packages we should use:

npm i --only=production