8 Using JavaScript: the big picture

In this chapter, I’d like to paint the big picture: what are you learning in this book, and how does it fit into the overall landscape of web development?

8.1 What are you learning in this book?

This book teaches the JavaScript language. It focuses on just the language, but offers occasional glimpses at two platforms where JavaScript can be used:

• Web browser
• Node.js

Node.js is important for web development in three ways:

• You can use it to write server-side software in JavaScript.
• You can also use it to write software for the command line (think Unix shell, Windows PowerShell, etc.). Many JavaScript-related tools are based on (and executed via) Node.js.
• Node’s software registry, npm, has become the dominant way of installing tools (such as compilers and build tools) and libraries – even for client-side development.

8.2 The structure of browsers and Node.js

The structures of the two JavaScript platforms web browser and Node.js are similar (figure 8.1):

• The foundational layer consists of the JavaScript engine and platform-specific “core” functionality.
• Two APIs are hosted on top of this foundation:
  • The JavaScript standard library is part of JavaScript proper and runs on top of the engine.
  • The platform API are also available from JavaScript – it provides access to platform-specific functionality. For example:
    • In browsers, you need to use the platform-specific API if you want to do anything related to the user interface: react to mouse clicks, play sounds, etc.
    • In Node.js, the platform-specific API lets you read and write files, download data via HTTP, etc.

8.3 JavaScript references

If you have a question about JavaScript, I can recommend the following online resources:

• MDN Web Docs: cover various web technologies such as CSS, HTML, JavaScript, and more. An excellent reference.
• Node.js Docs: document the Node.js API.
• ExploringJS.com: My other books cover various aspects of web development:
  • “Deep JavaScript: Theory and techniques” describes JavaScript at a level of detail that is beyond the scope of “Exploring JavaScript”.
  • “Tackling TypeScript: Upgrading from JavaScript”
  • “Shell scripting with Node.js”

8.4 Further reading

• “Next steps: overview of web development” (§48) provides a more comprehensive look at web development.