T. J. Crowder

JavaScript

The New Toys

• Broschiertes Buch

Produktbeschreibung

All of JavaScript's newest features, in depth, made easy to understand.

JavaScript is a rapidly changing language and it can be challenging to keep up with all the new toys being added. JavaScript: The New Toys explores the newest features of the world's most popular programming language while also showing readers how to track what's coming next. After setting the stage by covering who manages the process of improving JavaScript, how new features get introduced, terminology, and a high-level overview of new features, it details each new or updated item in depth, with example uses, possible pitfalls, and expert recommendations for updating old habits in light of new features. JavaScript: The New Toys:
_ Covers all the additions to JavaScript in ES2015-ES2020 plus a preview of what's coming next
_ Explores the latest syntax: nullish coalescing, optional chaining, let and const, class syntax, private methods, private fields, new.target, numeric separators, BigInt, destructuring, default parameters, arrow functions, async functions, await, generator functions, ... (rest and spread), template literals, binary and octal literals, __ (exponentiation), computed property/method names, for-of, for-await-of, shorthand properties, and others
_ Details the new features and patterns including modules, promises, iteration, generators, Symbol, Proxy, reflection, typed arrays, Atomics, shared memory, WeakMap, WeakSet, and more
_ Highlights common pitfalls and explains how to avoid them
_ Shows how to follow the improvements process and even participate in the process yourself
_ Explains how to use new features even before they're widely supported

With its comprehensive coverage and friendly, accessible style, JavaScript: The New Toys provides an invaluable resource for programmers everywhere, whether they work in web development, Node.js, Electron, Windows Universal Apps, or another JavaScript environment.

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Produktdetails

• Verlag: Wiley & Sons
• Artikelnr. des Verlages: 1W119367950
• 1. Auflage
• Seitenzahl: 608
• Erscheinungstermin: 21. Juli 2020
• Englisch
• Abmessung: 235mm x 188mm x 28mm
• Gewicht: 990g
• ISBN-13: 9781119367956
• ISBN-10: 1119367956
• Artikelnr.: 45801154

Autorenporträt

About the author T.J. Crowder is a software engineer with 30 years of experience, including over 15 years of professional work in JavaScript. He runs Farsight Software, a software contracting and product company. He's often found helping people on Stack Overflow, where he's a top 10 all-time contributor and the top JavaScript contributor. When not working or writing, he...no, sorry, he's always working or writing - or spending time with his wonderful, supportive wife and fantastic son. Visit us at www.wiley.com for free code samples.

Inhaltsangabe

Introduction xxxi

Chapter 1: The New Toys In ES2015-ES2020, and Beyond 1

Definitions, Who's Who, and Terminology 2

What are the "New Toys"? 4

How Do New Toys Get Created? 6

Keeping Up with the New Toys 9

Using Today's Toys in Yesterday's Environments, and Tomorrow's Toys Today 10

Review 15

Chapter 2: Block-Scoped Declarations: Let and Const 17

An Introduction to let and const 18

True Block Scope 18

Repeated Declarations are an Error 19

Hoisting and the Temporal Dead Zone 20

A New Kind of Global 22

const: Constants for JavaScript 24

Block Scope in Loops 26

Old Habits to New 36

Chapter 3: New Function Features 39

Arrow Functions and Lexical this, super, etc. 40

Default Parameter Values 45

"Rest" Parameters 50

Trailing Commas in Parameter Lists and Function Calls 52

The Function name Property 53

Function Declarations in Blocks 55

Function Declarations in Blocks: Standard Semantics 57

Old Habits to New 60

Chapter 4: Classes 65

What is a Class? 66

Introducing the New class Syntax 66

Comparing with the Older Syntax 75

Creating Subclasses 77

Leaving Off Object.prototype 97

new.target 98

class Declarations vs. class Expressions 101

More to Come 103

Old Habits to New 104

Chapter 5: New Object Features 105

Computed Property Names 106

Shorthand Properties 107

Getting and Setting an Object's Prototype 107

Method Syntax, and super Outside Classes 109

Symbol 112

New Object Functions 120

Symbol.toPrimitive 123

Property Order 125

Property Spread Syntax 127

Old Habits to New 128

Chapter 6: Iterables, Iterators, For-Of, Iterable Spread, Generators 131

Iterators, Iterables, the for-of Loop, and Iterable Spread Syntax 131

Generator Functions 146

Old Habits to New 163

Chapter 7: Destructuring 165

Overview 165

Basic Object Destructuring 166

Basic Array (and Iterable) Destructuring 169

Defaults 170

Rest Syntax in Destructuring Patterns 172

Using Different Names 173

Computed Property Names 174

Nested Destructuring 174

Parameter Destructuring 175

Destructuring in Loops 178

Old Habits to New 179

Chapter 8: Promises 181

Why Promises? 182

Promise Fundamentals 182

Using an Existing Promise 186

Adding Handlers to Already Settled Promises 201

Creating Promises 202

Other Promise Utility Methods 207

Promise Patterns 210

Handle Errors or Return the Promise 210

Promises in Series 211

Promises in Parallel 213

Promise Subclasses 218

Old Habits to New 219

Chapter 9: Asynchronous Functions, Iterators, and Generators 221

async Functions 222

async Iterators, Iterables, and Generators 232

for-await-of 238

Old Habits to New 238

Chapter 10: Templates, Tag Functions, and New String Features 241

Template Literals 241

Improved Unicode Support 250

Iteration 255

New String Methods 256

Updates to the match, split, search, and replace Methods 259

Old Habits to New 260

Chapter 11: New Array Features, Typed Arrays 263

New Array Methods 264
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