Into YDKJS

This is summary of last, third, chapter of first volume, Up & Going, in series, You Don’t Know JS, of 6 books written by Kyle Simpson. In this chapter author is talking about what this series is all about?

In this series we’ll be learning all parts of JS and not just some good parts of JS. It’ll chalenge the readers to go beyond the comfort zone and ask the why language is behaving the way we encounter?

Scope & Closure

In this part, we’ll get get a clear picture of how scoping of variable really works in JavaScript. We’ll start this title y busting the myth that JS in interpreted language not compiled. JS engine compiles the code right before execution. So, we’ll be using deeper understanding of compiler’s approach of how it finds and executes variable and function declaration. Then we go on looking for how hoisting works. And based on understanding of lexical scope we’ll see how closure works.

This & Object Prototypes

In this part, we’ll break the myths related to this keyword that ‘this’ refers to function it appeared in. Actually ‘this’ keywords refers to the object that calls the function. Closely related to ‘this’ is object prototype. While we have class present and we can use inheritance. It’s better to learn, prototype mechanism and behaviour delegation. It’s more elegant, powerful design pattern than class and inheritance.

Types & Grammar

In this section, we’ll mainly learn about Type coercion. We’ll see type coercion is not confusing as we all see it and we’ll get to know that how beautiful it is. Coercion is incredibly useful and makes our code better.

Async & Performance

JavaScript is single threaded and synchronous language. But in modern application of modern world there are lot of async operation that we need to perform. So this books will start by clearing confusions related to lot of concepts like ‘async’, ‘parallel’ and ‘concurrent’ and will explain how these apply and don’t apply to JS. Then we’ll move forward explaining callback, promise and generators. We’ll see why callback isn’t effective way to deal with async operation and we’ll explore how to use generators and promises together to perform better async operation.

ES6 & Beyond

No matter how much we’ve learnt JS. JS will keep evolving and and speed of evolution of JS will increase only. So, we’ll never fully understand JS. In this book we’ll explore the new addition in ES6 and what can we expect in upcoming version of JS. We’ll learn about ES6 features like async-await, generators, promises, default parameters, block and many more.

In first part of this books we’ll get glance and road map of everything that we need to learn to use new features of new and improved JS and in second part of book we’ll get to know what we can expect in upcoming JS version upgrade.

‘You don’t know JS’ isn’t a negative term but a realisation that learning JS can’t be end goal but a process. We don’t know it yet completely but we’ll keep digging deep.