Installing packages (dependencies vs devDependencies) in Node.js - Quick Revision & Summary

Recall & Review

beginner

What is the difference between dependencies and devDependencies in a Node.js project?

dependencies are packages needed for the app to run in production.<br>devDependencies are packages only needed during development, like testing or building tools.

beginner

Which command installs a package as a devDependency using npm?

Use npm install <package> --save-dev or the shortcut npm i <package> -D.

intermediate

Why should you separate dependencies and devDependencies?

Separating helps keep production installs small and fast by only installing what the app needs to run.<br>It also avoids shipping unnecessary tools to users.

intermediate

What happens if you run npm install in production mode?

Only dependencies are installed, skipping devDependencies to save space and time.

beginner

How can you check which packages are listed as dependencies or devDependencies?

Look inside the package.json file under the dependencies and devDependencies sections.

Which npm command installs a package as a regular dependency?

A npm install express

B npm install express --save-dev

C npm install express -D

D npm uninstall express

npm install express installs express as a regular dependency.

Where are devDependencies listed in a Node.js project?

A In the <code>node_modules</code> folder only

B In the <code>package.json</code> file under <code>devDependencies</code>

C In the <code>package-lock.json</code> file

D In the <code>README.md</code> file

devDependencies are listed in package.json under the devDependencies section.

What is the main reason to use devDependencies?

A To update packages automatically

B To include packages needed in production

C To include packages only needed during development

D To uninstall packages

devDependencies are for packages used only during development, like testing or building.

If you run npm install --production, what happens?

A Only <code>dependencies</code> are installed

B Only <code>devDependencies</code> are installed

C Both <code>dependencies</code> and <code>devDependencies</code> are installed

D No packages are installed

The --production flag installs only dependencies, skipping devDependencies.

Which of these is NOT a devDependency?

A A code linter like ESLint

B A bundler like Webpack

C A testing library like Jest

D A runtime framework like Express

Express is usually a runtime dependency, not a devDependency.

Explain the difference between dependencies and devDependencies in a Node.js project and why it matters.

Think about what packages your app needs when running versus when building or testing.

Describe how you would install a package only for development and how to check it in your project files.

Focus on the npm command and where the info is stored.