To avoid reinventing the wheel, engineers create and share standalone programs for a specific use case as a package for others to easily incorporate into their projects.

NPM’s job is to manage those packages, this includes package creation, package hosting, package downloading, package versioning, package management in a project and more.

Engineers use a file called package.json to manage the package dependencies in a JavaScript project.

In 2016, many major websites went down because a heavily depended upon NPM package was unpublished. This package only had 11 lines of code.

You don’t have to use NPM as the package manager for your JavaScript projects, there are other alternatives such as Yarn, an initiative started by a team of engineers at Facebook.

Also, you don’t have to use a package manager at all. You can always download the full source code of the packages you want to use and import them into your projects. But this means you will have to deal with package dependencies, versioning, updates manually. Which quickly becomes laborious as the number of dependencies increases.