What is the --save option for npm install?

Question

I saw some tutorial where the command was:

npm install --save 

What does the --save option mean?

Answer 1

Update npm 5:

As of npm 5.0.0, installed modules are added as a dependency by default, so the --save option is no longer needed. The other save options still exist and are listed in the documentation for npm install.

Original answer:

Before version 5, NPM simply installed a package under node_modules by default. When you were trying to install dependencies for your app/module, you would need to first install them, and then add them (along with the appropriate version number) to the dependencies section of your package.json.

The --save option instructed NPM to include the package inside of the dependencies section of your package.json automatically, thus saving you an additional step.

In addition, there are the complementary options --save-dev and --save-optional which save the package under devDependencies and optionalDependencies, respectively. This is useful when installing development-only packages, like grunt or your testing library.

Answer 2

Update as of npm 5:

As of npm 5.0.0, installed modules are added as a dependency by default, so the --save option is no longer needed. The other save options still exist and are listed in the documentation for npm install.

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Original Answer:

To add package in dependencies:

npm install my_dep --save 

or

npm install my_dep -S 

or

npm i my_dep -S 

To add package in devDependencies

npm install my_test_framework --save-dev 

or

npm install my_test_framework -D 

or

npm i my_test_framework -D 

package.json