npm dependencies and devDependencies
When is a package a dependency, and when is it a dev dependency?
When you install an npm package using npm install <package-name>, you are installing it as a dependency.
The package is automatically listed in the package.json file, under the dependencies list (as of npm 5: before you had to manually specify --save).
When you add the -D flag, or --save-dev, you are installing it as a development dependency, which adds it to the devDependencies list.
Development dependencies are intended as development-only packages, that are unneeded in production. For example testing packages, webpack or Babel.
When you go in production, if you type npm install and the folder contains a package.json file, they are installed, as npm assumes this is a development deploy.
You need to set the --production flag (npm install --production) to avoid installing those development dependencies.
THE VALLEY OF CODE
THE WEB DEVELOPER's MANUAL
You might be interested in those things I do:
- Learn to code in THE VALLEY OF CODE, your your web development manual
- Find a ton of Web Development projects to learn modern tech stacks in practice in THE VALLEY OF CODE PRO
- I wrote 16 books for beginner software developers, DOWNLOAD THEM NOW
- Every year I organize a hands-on cohort course coding BOOTCAMP to teach you how to build a complex, modern Web Application in practice (next edition February-March-April-May 2024)
- Learn how to start a solopreneur business on the Internet with SOLO LAB (next edition in 2024)
- Find me on X