What is --save-dev in npm install?

--save-dev is a command-line option used to install packages needed during the project's development phase.

When you pass --save-dev to the npm install package-name command, it downloads all the package files to the node_modules folder and makes an entry of that package to the devDependencies section of the package.json file.

In the package.json file, the devDependencies field has the list of all the packages which are required for development purposes. For example, packages such as nodemon, mocha, eslint, etc., are not needed in a production environment, so you install them using the --save-dev option.

Note: -D is an alias of --save-dev, which means you can use either --save-dev or -D with the npm install command.

Here is how you use --save-dev with the npm install command.

$npm install package-name --save-dev
$npm install package-name -D

Let's see how --save-dev option installs the package with the help of an example. Suppose we want to install the nodemon package that automatically reloads your project. This package has no use in production.

Before we install it, let's see the content of the package.json file.

package.json file before installing nodemon

Now run the npm install command and pass nodemon and --save-dev option.

$npm install nodemon --save-dev

After this, open the package.json file to confirm that the nodemon package is installed as devDependencies.

package.json file after installing nodemon

Recommended Posts