Some computer programs, such as scientific simulations and machine learning models, are compute-bound: they run continuously, without pause, until they have computed their result. Most real-world computer programs, however, are significantly asynchronous. This means that they often have to stop computing while waiting for data to arrive or for some event to occur. JavaScript programs in a web browser are typically event-driven, meaning that they wait for the user to

This chapter covers a number of advanced JavaScript features that are not commonly used in day-to-day programming but that may be valuable to programmers writing reusable libraries and of interest to anyone who wants to tinker with the details about how JavaScript objects behave. 本章涵盖了一些高级的JavaScript特性，这些特

The JavaScript language was created in 1994 with the express purpose of enabling dynamic behavior in the documents displayed by web browsers. The language has evolved significantly since then, and at the same time, the scope and capabilities of the web platform have grown explosively. Today, JavaScript programmers can think of the web as a full-featured platform for application development. Web browsers specialize in the display of formatted text and

Node is JavaScript with bindings to the underlying operating system, making it possible to write JavaScript programs that read and write files, execute child processes, and communicate over the network. This makes Node useful as a: Node是绑定到底层操作系统的JavaScript，使编写JavaS

Congratulations on reaching the final chapter of this book. If you have read everything that comes before, you now have a detailed understanding of the JavaScript language and know how to use it in Node and in web browsers. This chapter is a kind of graduation present: it introduces a handful of important programming tools that many JavaScript programmers find useful, and also describes two widely used extensions to the