Advanced JavaScript Unleashed: Master Advanced JavaScript Concepts like Prototypes, Symbols, Generators, and More

What is JavaScript....7

Course Overview....7

Prerequisites....7

Running code examples....8

Who is this course for?....8

History of JavaScript....9

Standardization of the JavaScript language....10

Ecma International, TC39....10

Proposals process....11

Track upcoming features....13

How is ECMAScript versioned?....13

JIT Compiler....15

JavaScript Engine....16

Types of execution contexts....21

Execution context phases....22

Stack overflow....35

Automatic garbage collection....37

Hoisting....38

“var” declarations....38

Function declarations....39

Function declarations inside blocks....40

Class declarations....44

Temporal Dead Zone (TDZ)....45

Function and class expressions....46

Common misconception about hoisting....47

Scope....49

Lexical scope....49

Avoid polluting the global scope....51

Implicit globals....52

Shadowing declarations....54

Function parameter scope....55

Function expression name scope....58

Block Scope....59

Module Scope....59

Scope Chain....60

Coercion....63

ToPrimitive....65

ToNumber....75

ToString....76

ToBoolean....77

Summary of abstract equality operator....78

Addition Operator....82

Relational operators....83

Closures....92

What is a closure?....92

How do closures work?....93

How are different scopes linked?....95

What causes this problem?....102

How to resolve this problem?....103

Prototypes....111

How are objects linked?....111

The “prototype” property....112

Getting prototype of any object....114

Object.prototype - parent of all objects....115

“Function” function....118

Problems with __proto__....121

Object.create method....123

Null prototype object....123

ES2015 classes....128

‘this’ keyword....130

Function context....130

Global context....132

Constructor function context....133

Class context....133

DOM event handler context....134

Arrow functions to the rescue....138

Borrowing methods....142

Chain constructor calls....143

Revisit “this” problem....144

“this” vs globalThis....146

Symbol....149

Symbols and privacy....151

Adding a description to symbols....153

Symbol.toPrimitive....156

Symbol.toStringTag....156

Symbol.isConcatSpreadable....157

Asynchronous JavaScript....159

What does asynchronous mean?....159

Asynchronous JavaScript....160

Problems with callbacks....164

What is an event loop?....167

Promise states....172

Promise instance methods....173

Creating promises....176

Using promises with callback-based API....178

Promise specification....179

Promise vs thenable....179

then promise....182

catch promise....186

finally promise....190

Making sense of promise chaining....193

Rejection handler in then vs catch....202

Concurrent requests....203

Request timeout....204

async functions....208

await keyword....210

Multiple await expressions....212

Error handling....214

Returning vs awaiting promise....215

Awaiting non-promise value....219

Unnecessary use of the Promise Constructor....227

Incorrect Error Handling....228

Converting promise rejection into fulfillment....230

Async executor function....232

Iterators and Generators....234

Iterables....234

Iterators....235

Iterator prototype....237

Making custom iterable objects....239

Infinite sequence....242

Implementing iterators....243

Consuming values....244

Delegating to other iterators....246

Further reading....247

for await…of loop....251

Debugging JavaScript....252

Wrap up....261

Understand the confusing parts of JavaScript - Become a confident JavaScript pro by unraveling the most challenging aspects of the language. With easy-to-understand explanations and code examples, you’ll gain a solid understanding of JavaScript's most complex features in Advanced JavaScript Unleashed.

With the continued popularity of JavaScript frontend frameworks like React, Vue, or Angular, having a solid understanding of the more complicated parts of JavaScript is more important than ever. And with JavaScript being a dynamically typed language, it has some quirks. Some of its features can be confusing or hard to understand, for beginners and intermediate developers alike.

After answering the questions of hundreds of JavaScript developers, Unpacking Intermediate JavaScript book author, Yousaf Khan, realized that the same few topics kept coming up over and over. There were fundamental aspects of JavaScript that developers were missing!

This book aims to make it attainable for anyone to develop a deeper understanding of JavaScript by providing easy-to-understand explanations of all the important and hard-to-understand topics that keep many devs stagnant, producing the most bugs and unmaintainable code.

Unpacking Intermediate JavaScript aims to make it attainable for anyone to develop a deeper understanding of the JavaScript language by providing clear and concise explanations of core mid-level topics. The book will cover closures, coercion, asynchronous nature of Javascript, hoisting, and event loop. But also dive into advanced topics like promises, async-await, and more.

With multiple popular frontend JavaScript frameworks in use today (React, Vue, or Angular,) having a solid understanding of JavaScript makes it easy to learn and work with these frameworks.The carefully curated knowledge presented in this book will help you develop a solid understanding of the JavaScript language, and in turn will make it easy for you to work with different JavaScript frameworks.