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Professional JavaScript for Web Developers

You're reading from   Professional JavaScript for Web Developers Discover an easy-to-learn guide to upgrade your JavaScript skills

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Product type Paperback
Published in Nov 2019
Publisher Wiley
ISBN-13 9781119366447
Length 1144 pages
Edition 4th Edition
Languages
Tools
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Author (1):
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Matt Frisbie Matt Frisbie
Author Profile Icon Matt Frisbie
Matt Frisbie
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Table of Contents (37) Chapters Close

COVER FREE CHAPTER
FOREWORD
INTRODUCTION 1 What Is JavaScript? 2 JavaScript in HTML 3 Language Basics 4 Variables, Scope, and Memory 5 Basic Reference Types 6 Collection Reference Types 7 Iterators and Generators 8 Objects, Classes, and Object-Oriented Programming 9 Proxies and Reflect 10 Functions 11 Promises and Async Functions 12 The Browser Object Model 13 Client Detection 14 The Document Object Model 15 DOM Extensions 16 DOM Levels 2 and 3 17 Events 18 Animation and Graphics with Canvas 19 Scripting Forms 20 JavaScript APIs 21 Error Handling and Debugging 22 XML in JavaScript 23 JSON 24 Network Requests and Remote Resources 25 Client-Side Storage 26 Modules 27 Workers 28 Best Practices A ES2018 and ES2019 B Strict Mode C JavaScript Libraries and Frameworks D JavaScript Tools INDEX
END USER LICENSE AGREEMENT

PROXY PATTERNS

The Proxy API allows you to introduce some incredibly useful patterns into your code.

Tracking Property Access

The nature of get, set, and has affords you total insight into when object properties are being accessed and inspected. If you provide a trapped proxy to an object throughout your application, you will be able to see exactly when and where this object is accessed:

const user = {
 name: 'Jake'
};

const proxy = new Proxy(user, {
 get(target, property, receiver) {
  console.log('Getting ${property}');

  return Reflect.get(…arguments);
 },
 set(target, property, value, receiver) {
  console.log('Setting ${property}=${value}');

  return Reflect.set(…arguments);
 }
});

proxy.name;   // Getting name
proxy.age = 27; // Setting age=27

Hidden Properties

The innards of proxies are totally hidden to remote code so it is very easy to conceal the existence of properties on the target object. For example:

const hiddenProperties...
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