JavaScript Package Managers

What are they?

As a web developer, you are sure to use a smaller or larger number of third-party libraries and tools. After a while, it gets really hard to maintain and keep all of them and their dependencies up to date. For that reason, it was necessary to develop JavaScript packages and tools to manage them. Packages (or modules, but in some cases, they are not the same thing) are not strange to some other development languages and environments and they have been around for a while.

JavaScript package is basically one or more libraries grouped (or packaged) into a single package. Every package has one or more functionalities like animation, form validation, file reading or basically anything else that can be done in JavaScript. You are sure to find packages for all common tasks so you won't need to do it yourself from scratch.

Package managers are tools that are used for installing, maintaining and upgrading JavaScript packages and their dependencies which are included in your project and are necessary for your app to work properly. Here we will focus on package managers since packages themselves are not the topic. Depending on the popularity of a package manager you will be able to find a different number of packages to use.

Package managers

As mentioned above packages managers are used to manage third-party packages that you include into your project. There are several JavaScript package managers available like npm, bower, Yarn, Webpack or Duo. Basically, all package managers work on the same principle. They work with your project code, dependency code (libraries you included) and a manifest file which contains information on your project and it's dependencies. Depending on the package manager they may be some other files as well.

Flat and nested dependencies

There are two basic ways of managing dependencies, flat and nested. Flat dependencies include dependent files on the same level, so your project code and all other dependencies can access a particular dependency. Nested dependencies manage dependencies on multiple levels and allow dependencies to have their own dependencies that can't be accessed by projects code or other dependencies.

In most cases, any of these methods will be fine. But in cases where, for example, several of your dependencies have the same dependency of their own but of the different version you will need to use the nested approach to make sure all dependencies are of proper version. With nested dependencies every dependency can isolate their own dependencies so you can have several versions of the same library in your project if necessary.

NPM

NPM stands for Node Package Manager. It is probably the most popular package manager out there. Looking at the name you could get an impression that it can only be used with NodeJS and only with the backend code. But this is not so, you can use it with both, backend and frontend code. You only need to make sure that the package you want to use can be used for the purpose you need it for (frontend or backend). Many packages nowadays can be used in both environments. There are several hundred thousand NPM packages in the repository so this is a good choice for any developer.

Bower

Bower is also one of the more popular packages manages. It was created at the time NPM could not be used for frontend apps but only with NodeJS and it gained popularity very quickly. It was developed in 2012. at Twitter. Bower also has thousands of packages in the repository including some very popular stuff like Bootstrap, Font Awesome or jQuery.

Yarn

It is a newer package manager as it was released in 2016. developed by the collaboration of several companies including Facebook and Google. Yarn was built for the ground up having security and performance in mind. It is fully compatible with the NPM registry and has basically the same feature set as NPM.

Conclusion

In this article, we tried to cover the basics of package managers and packages and described a few package managers we think are the most popular. If you are a developer and didn't use package managers until now it would be good to start not. It saves a lot of time and makes sure your projects will work properly. If you are a beginner it is probably best you start with some of the more popular ones. If you are an experienced developer with package manager experience we are sure you will find a package manager to fit your needs (it is more likely you already did).

Article by Matej Drabik, @Mars Spiders Global