Summary

In this chapter, you learned about a set of different module formats as alternatives to the CommonJS module format. You have been introduced to the current standard approach of writing ESMs, which brings a module system directly to the JavaScript language.

You also saw how alternative module formats such as AMD or UMD can be used to run JavaScript modules on other older JavaScript runtimes. We discussed that by using the specialized module loader, SystemJS, you can actually make use of truly convenient and current features as a web standard today. The need for import maps is particularly striking when talking about third-party dependencies.

You learned that most third-party dependencies are actually deployed in the form of packages. In this chapter, you also saw how a package.json file defines the root of a package and what kind of data may be included in package.json file.

In the next chapter, we will learn how packages using the discussed formats can be installed...