The following examples illustrate the differences:
npm add core_module
npm add core_module --include
npm add core_module --include-dev
What distinguishes these flag options in npm installations?
In my experience, the main difference between these flags lies in organization and function. When you use the flag corresponding to --save, the package is registered as a dependency, meaning it is required during runtime and needs to be installed in production environments. Alternatively, the flag similar to --save-dev saves the package under devDependencies, which is typically for tools that assist in development, such as testing frameworks or build tools. This clear separation helps avoid deploying unnecessary packages to production, keeping the environment lean and focused.
From my experience, using the two different flags helps maintain clarity in project dependencies. When using the regular save flag, the installed package becomes part of the runtime core, meaning it is required for the application to function properly in production. On the other hand, save-dev is used for packages that assist during the development cycle, such as testing tools or build helpers, and are not needed in production. This separation has helped me avoid bloated production environments and has streamlined troubleshooting by clearly separating development aids from runtime dependencies.