<div><p>No matter how much experience you have with JavaScript, odds are you don’t fully understand the language. This concise yet in-depth guide takes you inside scope and closures, two core concepts you need to know to become a more efficient and effective JavaScript programmer. You’ll learn how and why they work, and how an understanding of closures can be a powerful part of your development skillset.</p><p>Like other books in the "You Don’t Know JS" series, <i>Scope and Closures</i> dives into trickier parts of the language that many JavaScript programmers simply avoid. Armed with this knowledge, you can achieve true JavaScript mastery.</p><ul><li>Learn about scope, a set of rules to help JavaScript engines locate variables in your code</li><li>Go deeper into nested scope, a series of containers for variables and functions</li><li>Explore function- and block-based scope, “hoisting”, and the patterns and benefits of scope-based hiding</li><li>Discover how to use closures for synchronous and asynchronous tasks, including the creation of JavaScript libraries</li></ul></div>