How JavaScript Works: Master the Basics of JavaScript and Modern Web App Development

Table of Contents....4 About the Author....12 About the Technical Reviewer....13 Introduction....14 Chapter 1: Introduction to JavaScript....15 JavaScript Fundamentals....16 JavaScript’s Type Classification....17 What Is JavaScript Used For?....18 Writing JavaScript....19 Setting Up a Code Editor....21 Starting Up Our Code....22 How to Get Started with Writing Back-End JavaScript....23 Creating Node.js JavaScript Projects....25 JavaScript Support....26 Summary....28 Chapter 2: Code Structure and Logical Statements....29 Getting Started....29 Common Code Conventions....31 Semicolons....31 Spacing....32 Variable and Function Naming....33 JavaScript Variables....33 Setting Variables with let....34 Block Scoping with Variables....35 Setting Variables with var....36 Setting Variables with const....37 Mutation of const Variables....38 Defining Variables Without Values....39 Assignment Operators....40 Variable Concatenation....41 Template Literals....42 JavaScript Comments....43 Logical Statements....44 If…else Statements....44 Switch Statements....47 Defaulting to a Clause with Switch Statements....49 Equality with Switch Statements....49 Block Scoping with Logical Statements....50 Conditional Operator in Variables....52 Logical Statement Comparison Operators....52 Logical Statement Logical Operators....55 Summary....56 Chapter 3: Introduction to Objects, Arrays....57 Arrays....57 Getting the Length of an Array....58 Getting the Last Element of an Array....59 Array Manipulation Methods....60 Push and Unshift....61 Pop and Shift....61 Splice....62 Objects....63 Accessing Object Data....65 The Dot Notation vs. Square Brackets with Objects....66 Destructuring Objects....67 Object Mutability....69 Non-mutable objects....70 Spread Syntax or the “Three Dots”....72 Prototype-Based Programming....73 Prototypical Inheritance....75 [[Prototype]] vs. prototype (and __proto__)....77 Object Shallow and Deep Copies....79 Summary....82 Chapter 4: Loops and Iterables....83 Loops....83 Break and Continue in Loops....87 Loop Labels....87 Iteration....89 Iterables and For Loops....90 Array forEach methods....92 String Iteration....92 Iteration Protocol....93 Objects Are Not Iterable by Default....96 Summary....99 Chapter 5: References, Values, and Memory Management....100 Introduction....100 Stacks....101 The Event Loop....103 The Heap....106 Object and Reference Equality....107 Comparing Object Equality....109 Summary....110 Chapter 6: Functions and Classes....111 Introduction to Functions....111 Running Arguments with the “Three Dots”....114 Alternative Ways to Call Functions....114 Unnamed Function Expressions....115 Anonymous Functions....115 Functions with Arrow Notation....116 Functions and the “this” Keyword....116 Sloppy Mode....117 Arrow Notation Functionality with this....118 Calling Functions with Context....119 Constructor Functions in JavaScript....122 Additional Function Methods....125 Getters and Setters....126 Generator Functions....127 Classes....129 Classes and Constructor Functions....129 Class Methods....130 Class Method Types....133 Static Method Fields....134 Private Method Fields....136 Class Inheritance via Extends....136 Class Inheritance Super Keyword....139 Summary....141 Chapter 7: Types....142 Primitive Types....142 Primitive Wrappers....144 Using Wrappers to Create Types....147 The Number Type and NaN....148 Number Type Mathematics....150 Mathematical Methods....152 The Date Type....154 The Symbol Type....158 Truthy and Falsy Types....160 Truthy and Falsy Operators....161 Logical AND Operator....161 Logical OR Operator....162 Nullish Coalescing....163 Optionality....164 Summary....168 Chapter 8: Manipulating and Interacting with HTML....170 Window and Document Objects....170 The Window Object....171 The Document Object Model....173 Selecting HTML Elements....174 The Order of HTML....176 NodeLists and HTMLCollections....178 Manipulating HTML After Selection....181 Adding Events to HTML Elements....184 Creating a Modal Window....184 Creating a Counter....187 Event Types....188 Pointers, Touch, and Mouse....190 Event Capturing, Targeting, and Bubbling....191 Capturing Phase....194 Other Event Options....196 Live Data Using Events....198 Drag and Drop....201 The e variable....205 Creating New Elements with JavaScript....206 Manipulating CSS with JavaScript....210 HTMLElements and Changing Styles in JavaScript....210 Adding New Style Sheets to HTML Pages....211 Setting CSS Variables....211 Getting CSS Properties and HTML Dimensions....212 Summary....214 Chapter 9: Maps and Sets....216 Sets....216 Modifying Sets....218 Checking Set Membership....219 Checking Set Size....219 Merging Sets....219 Set Iteration and Values....220 Set Keys and Values....222 Maps....223 Retrieving Map Properties....226 Checking for Key Existence on a Map....228 Telling How Big a Javascript Map Is....228 Iterating, Merging, and Accessing Maps....229 Keys and Values in Maps....230 Serialization of Maps in JavaScript....232 Summary....233 Chapter 10: Fetching Data, APIs, and Promises....234 What Are APIs?....235 Understanding HTTP....237 RESTful Design....239 Understanding APIs Through a Node.JS Web Server....241 Testing Endpoints with Postman....247 The Benefits of APIs....247 Sending Data to APIs with JSON....249 The fetch Function....251 A Deep Dive into Fetch Options....254 body....255 mode....255 method....255 cache....256 credentials....256 headers....256 redirect....257 referrer....257 referrerPolicy....257 integrity....258 keepalive....258 Asynchronicity and Promises....259 Promise Methods: then, finally, and catch....261 catch and finally....262 The await Keyword....263 Useful Promise Methods....264 Promise.allSettled....265 Promise.all....266 Promise.race....267 Promise.any....268 Summary....269 Chapter 11: Introduction to Web APIs....270 Web APIs....270 Frequently Used Web APIs....272 URL API....273 Web Storage API....273 Web Notifications API....276 History API....277 Summary....278 Chapter 12: Errors and the Console....280 The Console Object....280 Console Errors, Debugs, Warnings, and Info....281 Console Tracing....281 Console Assertion....282 Console Timing....282 Console Counting....284 Other Useful Console Methods....285 Console Grouping....285 Console Tables....286 Errors and Exceptions....288 try…catch....289 finally....290 Generating Errors....292 Handling Specific Errors....293 Summary....294 Chapter 13: The Canvas....295 Introduction....296 Drawing and Images....298 Drawing Rectangles....298 Drawing Circles....301 Drawing Triangles....303 Drawing Images....305 Drawing Text....307 Interactivity and Creating a Drawing Application....309 Animations....313 Summary....315 Chapter 14: Web Workers and Multithreading....316 Introduction....316 Using Web Workers....318 Sending Messages to and from Web Workers....318 Restrictions on Web Workers....320 Conclusion....322 Index....323