npm Development Dependencies

When managing package dependencies, there are both dependencies and development dependencies. Third-party packages that are installed also have their own dependencies and development dependencies. The installation logic for these package dependencies needs to be clarified.

npm i

During local development, we typically run npm i, which installs both direct dependencies and direct development dependencies. However, development dependencies of third-party packages are not installed. This makes sense because packages themselves are published and considered to be in production mode, so there’s no need to install their development dependencies.

Of course, with dependencies and indirect dependencies plus package versions, multiple versions of the same package can coexist, which is also important to note.

–production

When running npm i, you can specify the mode explicitly. In production mode, development dependencies are not installed. This is mainly used when deploying Node.js services to production, where development-related packages (like TypeScript) are often not needed. This can further improve deployment speed.