Zack's Learning Journal

Zack's Learning Journal

--save VS --save-dev

UpdatedJanuary 21, 2025

•1 min read

When installing npm packages, there are two options provided:

—save (-S)
—save-dev (-D)

So what is the diff?

npm install <package> —save

Is equivalent to npm install <package>, which is the default behavior.
It install the package under node_modules, and add the package’s version information into the package.json’s dependencies.

npm install <package> —save-dev

Not the default behavior, === npm install <package> -D.
It install the package under node_modules, and add the package’s version information into the package.json’s devDependencies.
These packages would not be install in prod env.
Suitable for packages that would only be used in dev env, like eslint, webpack, @types/react (type definition packages, provided by TS community)

Note: the reason @types/react exist only in the dev env is

Type definitions are only used during development to provide code hints and type checking
These type definitions are not needed in the production environment
All type information is removed in the compiled JavaScript code

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Zack's Learning Journal

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A digital garden where I document interesting knowledge discoveries and tricky technical challenges encountered in my daily work.

--save VS --save-dev