The Wide, Wide Sea

JavaScript is the programming language of the web and is used by more software developers today than any other programming language. For nearly 25 years this best seller has been the go-to guide for JavaScript programmers. The seventh edition is fully updated to cover the 2020 version of JavaScript, and new chapters cover classes, modules, iterators, generators, Promises, async/await, and metaprogramming. You’ll find illuminating and engaging example code throughout. This book is for programmers who want to learn JavaScript and for web developers who want to take their understanding and mastery to the next level. It begins by explaining the JavaScript language itself, in detail, from the bottom up. It then builds on that foundation to cover the web platform and Node.js. Topics include: * Types, values, variables, expressions, operators, statements, objects, and arrays * Functions, classes, modules, iterators, generators, Promises, and async/await * JavaScript’s standard library: data structures, regular expressions, JSON, i18n, etc. * The web platform: documents, components, graphics, networking, storage, and threads * Node.js: buffers, files, streams, threads, child processes, web clients, and web servers * Tools and language extensions that professional JavaScript developers rely on. Copyright Table of Contents Preface Section 1. Conventions Used in This Book Section 2. Example Code Section 3. O’Reilly Online Learning Section 4. How to Contact Us Section 5. Acknowledgments Chapter 1. Introduction to JavaScript 1.1 Exploring JavaScript 1.2 Hello World 1.3 A Tour of JavaScript 1.4 Example: Character Frequency Histograms 1.5 Summary Chapter 2. Lexical Structure 2.1 The Text of a JavaScript Program 2.2 Comments 2.3 Literals 2.4 Identifiers and Reserved Words 2.4.1 Reserved Words 2.5 Unicode 2.5.1 Unicode Escape Sequences 2.5.2 Unicode Normalization 2.6 Optional Semicolons 2.7 Summary Chapter 3. Types, Values, and Variables 3.1 Overview and Definitions 3.2 Numbers 3.2.1 Integer Literals 3.2.2 Floating-Point Literals 3.2.3 Arithmetic in JavaScript 3.2.4 Binary Floating-Point and Rounding Errors 3.2.5 Arbitrary Precision Integers with BigInt 3.2.6 Dates and Times 3.3 Text 3.3.1 String Literals 3.3.2 Escape Sequences in String Literals 3.3.3 Working with Strings 3.3.4 Template Literals 3.3.5 Pattern Matching 3.4 Boolean Values 3.5 null and undefined 3.6 Symbols 3.7 The Global Object 3.8 Immutable Primitive Values and Mutable Object References 3.9 Type Conversions 3.9.1 Conversions and Equality 3.9.2 Explicit Conversions 3.9.3 Object to Primitive Conversions 3.10 Variable Declaration and Assignment 3.10.1 Declarations with let and const 3.10.2 Variable Declarations with var 3.10.3 Destructuring Assignment 3.11 Summary Chapter 4. Expressions and Operators 4.1 Primary Expressions 4.2 Object and Array Initializers 4.3 Function Definition Expressions 4.4 Property Access Expressions 4.4.1 Conditional Property Access 4.5 Invocation Expressions 4.5.1 Conditional Invocation 4.6 Object Creation Expressions 4.7 Operator Overview 4.7.1 Number of Operands 4.7.2 Operand and Result Type 4.7.3 Operator Side Effects 4.7.4 Operator Precedence 4.7.5 Operator Associativity 4.7.6 Order of Evaluation 4.8 Arithmetic Expressions 4.8.1 The + Operator 4.8.2 Unary Arithmetic Operators 4.8.3 Bitwise Operators 4.9 Relational Expressions 4.9.1 Equality and Inequality Operators 4.9.2 Comparison Operators 4.9.3 The in Operator 4.9.4 The instanceof Operator 4.10 Logical Expressions 4.10.1 Logical AND (&&) 4.10.2 Logical OR (||) 4.10.3 Logical NOT (!) 4.11 Assignment Expressions 4.11.1 Assignment with Operation 4.12 Evaluation Expressions 4.12.1 eval() 4.12.2 Global eval() 4.12.3 Strict eval() 4.13 Miscellaneous Operators 4.13.1 The Conditional Operator (?:) 4.13.2 First-Defined (??) 4.13.3 The typeof Operator 4.13.4 The delete Operator 4.13.5 The await Operator 4.13.6 The void Operator 4.13.7 The comma Operator (,) 4.14 Summary Chapter 5. Statements 5.1 Expression Statements 5.2 Compound and Empty Statements 5.3 Conditionals 5.3.1 if 5.3.2 else if 5.3.3 switch 5.4 Loops 5.4.1 while 5.4.2 do/while 5.4.3 for 5.4.4 for/of 5.4.5 for/in 5.5 Jumps 5.5.1 Labeled Statements 5.5.2 break 5.5.3 continue 5.5.4 return 5.5.5 yield 5.5.6 throw 5.5.7 try/catch/finally 5.6 Miscellaneous Statements 5.6.1 with 5.6.2 debugger 5.6.3 “use strict” 5.7 Declarations 5.7.1 const, let, and var 5.7.2 function 5.7.3 class 5.7.4 import and export 5.8 Summary of JavaScript Statements Chapter 6. Objects 6.1 Introduction to Objects 6.2 Creating Objects 6.2.1 Object Literals 6.2.2 Creating Objects with new 6.2.3 Prototypes 6.2.4 Object.create() 6.3 Querying and Setting Properties 6.3.1 Objects As Associative Arrays 6.3.2 Inheritance 6.3.3 Property Access Errors 6.4 Deleting Properties 6.5 Testing Properties 6.6 Enumerating Properties 6.6.1 Property Enumeration Order 6.7 Extending Objects 6.8 Serializing Objects 6.9 Object Methods 6.9.1 The toString() Method 6.9.2 The toLocaleString() Method 6.9.3 The valueOf() Method 6.9.4 The toJSON() Method 6.10 Extended Object Literal Syntax 6.10.1 Shorthand Properties 6.10.2 Computed Property Names 6.10.3 Symbols as Property Names 6.10.4 Spread Operator 6.10.5 Shorthand Methods 6.10.6 Property Getters and Setters 6.11 Summary Chapter 7. Arrays 7.1 Creating Arrays 7.1.1 Array Literals 7.1.2 The Spread Operator 7.1.3 The Array() Constructor 7.1.4 Array.of() 7.1.5 Array.from() 7.2 Reading and Writing Array Elements 7.3 Sparse Arrays 7.4 Array Length 7.5 Adding and Deleting Array Elements 7.6 Iterating Arrays 7.7 Multidimensional Arrays 7.8 Array Methods 7.8.1 Array Iterator Methods 7.8.2 Flattening arrays with flat() and flatMap() 7.8.3 Adding arrays with concat() 7.8.4 Stacks and Queues with push(), pop(), shift(), and unshift() 7.8.5 Subarrays with slice(), splice(), fill(), and copyWithin() 7.8.6 Array Searching and Sorting Methods 7.8.7 Array to String Conversions 7.8.8 Static Array Functions 7.9 Array-Like Objects 7.10 Strings as Arrays 7.11 Summary Chapter 8. Functions 8.1 Defining Functions 8.1.1 Function Declarations 8.1.2 Function Expressions 8.1.3 Arrow Functions 8.1.4 Nested Functions 8.2 Invoking Functions 8.2.1 Function Invocation 8.2.2 Method Invocation 8.2.3 Constructor Invocation 8.2.4 Indirect Invocation 8.2.5 Implicit Function Invocation 8.3 Function Arguments and Parameters 8.3.1 Optional Parameters and Defaults 8.3.2 Rest Parameters and Variable-Length Argument Lists 8.3.3 The Arguments Object 8.3.4 The Spread Operator for Function Calls 8.3.5 Destructuring Function Arguments into Parameters 8.3.6 Argument Types 8.4 Functions as Values 8.4.1 Defining Your Own Function Properties 8.5 Functions as Namespaces 8.6 Closures 8.7 Function Properties, Methods, and Constructor 8.7.1 The length Property 8.7.2 The name Property 8.7.3 The prototype Property 8.7.4 The call() and apply() Methods 8.7.5 The bind() Method 8.7.6 The toString() Method 8.7.7 The Function() Constructor 8.8 Functional Programming 8.8.1 Processing Arrays with Functions 8.8.2 Higher-Order Functions 8.8.3 Partial Application of Functions 8.8.4 Memoization 8.9 Summary Chapter 9. Classes 9.1 Classes and Prototypes 9.2 Classes and Constructors 9.2.1 Constructors, Class Identity, and instanceof 9.2.2 The constructor Property 9.3 Classes with the class Keyword 9.3.1 Static Methods 9.3.2 Getters, Setters, and other Method Forms 9.3.3 Public, Private, and Static Fields 9.3.4 Example: A Complex Number Class 9.4 Adding Methods to Existing Classes 9.5 Subclasses 9.5.1 Subclasses and Prototypes 9.5.2 Subclasses with extends and super 9.5.3 Delegation Instead of Inheritance 9.5.4 Class Hierarchies and Abstract Classes 9.6 Summary Chapter 10. Modules 10.1 Modules with Classes, Objects, and Closures 10.1.1 Automating Closure-Based Modularity 10.2 Modules in Node 10.2.1 Node Exports 10.2.2 Node Imports 10.2.3 Node-Style Modules on the Web 10.3 Modules in ES6 10.3.1 ES6 Exports 10.3.2 ES6 Imports 10.3.3 Imports and Exports with Renaming 10.3.4 Re-Exports 10.3.5 JavaScript Modules on the Web 10.3.6 Dynamic Imports with import() 10.3.7 import.meta.url 10.4 Summary Chapter 11. The JavaScript Standard Library 11.1 Sets and Maps 11.1.1 The Set Class 11.1.2 The Map Class 11.1.3 WeakMap and WeakSet 11.2 Typed Arrays and Binary Data 11.2.1 Typed Array Types 11.2.2 Creating Typed Arrays 11.2.3 Using Typed Arrays 11.2.4 Typed Array Methods and Properties 11.2.5 DataView and Endianness 11.3 Pattern Matching with Regular Expressions 11.3.1 Defining Regular Expressions 11.3.2 String Methods for Pattern Matching 11.3.3 The RegExp Class 11.4 Dates and Times 11.4.1 Timestamps 11.4.2 Date Arithmetic 11.4.3 Formatting and Parsing Date Strings 11.5 Error Classes 11.6 JSON Serialization and Parsing 11.6.1 JSON Customizations 11.7 The Internationalization API 11.7.1 Formatting Numbers 11.7.2 Formatting Dates and Times 11.7.3 Comparing Strings 11.8 The Console API 11.8.1 Formatted Output with Console 11.9 URL APIs 11.9.1 Legacy URL Functions 11.10 Timers 11.11 Summary Chapter 12. Iterators and Generators 12.1 How Iterators Work 12.2 Implementing Iterable Objects 12.2.1 “Closing” an Iterator: The Return Method 12.3 Generators 12.3.1 Generator Examples 12.3.2 yield* and Recursive Generators 12.4 Advanced Generator Features 12.4.1 The Return Value of a Generator Function 12.4.2 The Value of a yield Expression 12.4.3 The return() and throw() Methods of a Generator 12.4.4 A Final Note About Generators 12.5 Summary Chapter 13. Asynchronous JavaScript 13.1 Asynchronous Programming with Callbacks 13.1.1 Timers 13.1.2 Events 13.1.3 Network Events 13.1.4 Callbacks and Events in Node 13.2 Promises 13.2.1 Using Promises 13.2.2 Chaining Promises 13.2.3 Resolving Promises 13.2.4 More on Promises and Errors 13.2.5 Promises in Parallel 13.2.6 Making Promises 13.2.7 Promises in Sequence 13.3 async and await 13.3.1 await Expressions 13.3.2 async Functions 13.3.3 Awaiting Multiple Promises 13.3.4 Implementation Details 13.4 Asynchronous Iteration 13.4.1 The for/await Loop 13.4.2 Asynchronous Iterators 13.4.3 Asynchronous Generators 13.4.4 Implementing Asynchronous Iterators 13.5 Summary Chapter 14. Metaprogramming 14.1 Property Attributes 14.2 Object Extensibility 14.3 The prototype Attribute 14.4 Well-Known Symbols 14.4.1 Symbol.iterator and Symbol.asyncIterator 14.4.2 Symbol.hasInstance 14.4.3 Symbol.toStringTag 14.4.4 Symbol.species 14.4.5 Symbol.isConcatSpreadable 14.4.6 Pattern-Matching Symbols 14.4.7 Symbol.toPrimitive 14.4.8 Symbol.unscopables 14.5 Template Tags 14.6 The Reflect API 14.7 Proxy Objects 14.7.1 Proxy Invariants 14.8 Summary Chapter 15. JavaScript in Web Browsers 15.1 Web Programming Basics 15.1.1 JavaScript in HTML Tags 15.1.2 The Document Object Model 15.1.3 The Global Object in Web Browsers 15.1.4 Scripts Share a Namespace 15.1.5 Execution of JavaScript Programs 15.1.6 Program Input and Output 15.1.7 Program Errors 15.1.8 The Web Security Model 15.2 Events 15.2.1 Event Categories 15.2.2 Registering Event Handlers 15.2.3 Event Handler Invocation 15.2.4 Event Propagation 15.2.5 Event Cancellation 15.2.6 Dispatching Custom Events 15.3 Scripting Documents 15.3.1 Selecting Document Elements 15.3.2 Document Structure and Traversal 15.3.3 Attributes 15.3.4 Element Content 15.3.5 Creating, Inserting, and Deleting Nodes 15.3.6 Example: Generating a Table of Contents 15.4 Scripting CSS 15.4.1 CSS Classes 15.4.2 Inline Styles 15.4.3 Computed Styles 15.4.4 Scripting Stylesheets 15.4.5 CSS Animations and Events 15.5 Document Geometry and Scrolling 15.5.1 Document Coordinates and Viewport Coordinates 15.5.2 Querying the Geometry of an Element 15.5.3 Determining the Element at a Point 15.5.4 Scrolling 15.5.5 Viewport Size, Content Size, and Scroll Position 15.6 Web Components 15.6.1 Using Web Components 15.6.2 HTML Templates 15.6.3 Custom Elements 15.6.4 Shadow DOM 15.6.5 Example: a Web Component 15.7 SVG: Scalable Vector Graphics 15.7.1 SVG in HTML 15.7.2 Scripting SVG 15.7.3 Creating SVG Images with JavaScript 15.8 Graphics in a 15.8.1 Paths and Polygons 15.8.2 Canvas Dimensions and Coordinates 15.8.3 Graphics Attributes 15.8.4 Canvas Drawing Operations 15.8.5 Coordinate System Transforms 15.8.6 Clipping 15.8.7 Pixel Manipulation 15.9 Audio APIs 15.9.1 The Audio() Constructor 15.9.2 The WebAudio API 15.10 Location, Navigation, and History 15.10.1 Loading New Documents 15.10.2 Browsing History 15.10.3 History Management with hashchange Events 15.10.4 History Management with pushState() 15.11 Networking 15.11.1 fetch() 15.11.2 Server-Sent Events 15.11.3 WebSockets 15.12 Storage 15.12.1 localStorage and sessionStorage 15.12.2 Cookies 15.12.3 IndexedDB 15.13 Worker Threads and Messaging 15.13.1 Worker Objects 15.13.2 The Global Object in Workers 15.13.3 Importing Code into a Worker 15.13.4 Worker Execution Model 15.13.5 postMessage(), MessagePorts, and MessageChannels 15.13.6 Cross-Origin Messaging with postMessage() 15.14 Example: The Mandelbrot Set 15.15 Summary and Suggestions for Further Reading 15.15.1 HTML and CSS 15.15.2 Performance 15.15.3 Security 15.15.4 WebAssembly 15.15.5 More Document and Window Features 15.15.6 Events 15.15.7 Progressive Web Apps and Service Workers 15.15.8 Mobile Device APIs 15.15.9 Binary APIs 15.15.10 Media APIs 15.15.11 Cryptography and Related APIs Chapter 16. Server-Side JavaScript with Node 16.1 Node Programming Basics 16.1.1 Console Output 16.1.2 Command-Line Arguments and Environment Variables 16.1.3 Program Life Cycle 16.1.4 Node Modules 16.1.5 The Node Package Manager 16.2 Node Is Asynchronous by Default 16.3 Buffers 16.4 Events and EventEmitter 16.5 Streams 16.5.1 Pipes 16.5.2 Asynchronous Iteration 16.5.3 Writing to Streams and Handling Backpressure 16.5.4 Reading Streams with Events 16.6 Process, CPU, and Operating System Details 16.7 Working with Files 16.7.1 Paths, File Descriptors, and FileHandles 16.7.2 Reading Files 16.7.3 Writing Files 16.7.4 File Operations 16.7.5 File Metadata 16.7.6 Working with Directories 16.8 HTTP Clients and Servers 16.9 Non-HTTP Network Servers and Clients 16.10 Working with Child Processes 16.10.1 execSync() and execFileSync() 16.10.2 exec() and execFile() 16.10.3 spawn() 16.10.4 fork() 16.11 Worker Threads 16.11.1 Creating Workers and Passing Messages 16.11.2 The Worker Execution Environment 16.11.3 Communication Channels and MessagePorts 16.11.4 Transferring MessagePorts and Typed Arrays 16.11.5 Sharing Typed Arrays Between Threads 16.12 Summary Chapter 17. JavaScript Tools and Extensions 17.1 Linting with ESLint 17.2 JavaScript Formatting with Prettier 17.3 Unit Testing with Jest 17.4 Package Management with npm 17.5 Code Bundling 17.6 Transpilation with Babel 17.7 JSX: Markup Expressions in JavaScript 17.8 Type Checking with Flow 17.8.1 Installing and Running Flow 17.8.2 Using Type Annotations 17.8.3 Class Types 17.8.4 Object Types 17.8.5 Type Aliases 17.8.6 Array Types 17.8.7 Other Parameterized Types 17.8.8 Read-Only Types 17.8.9 Function Types 17.8.10 Union Types 17.8.11 Enumerated Types and Discriminated Unions 17.9 Summary Index About the Author Colophon JavaScript is a powerful, object-based scripting language; JavaScript programs can be embedded directly into HTML web pages. When combined with the Document Object Model (DOM) defined by a web browser, JavaScript allows you to create Dynamic HTML (DHTML) content and interactive client-side web applications. JavaScript syntax is based on the popular programming languages C, C++, and Java, which makes it familiar and easy to learn for experienced programmers. At the same time, JavaScript is an interpreted scripting language, providing a flexible, forgiving environment in which new programmers can learn. * The Definitive Guide* provides a thorough description of the core JavaScript language and both the legacy and standard DOMs implemented in web browsers. The book includes sophisticated examples that show you how to handle common tasks such as validating form data, working with cookies, and creating portable DHTML animations. The book also contains detailed reference sections that cover the core JavaScript API, the legacy client-side API, and the W3C standard DOM API, documenting every JavaScript object, method, property, constructor, constant, function, and event handler in those APIs. This fourth edition of the bestselling JavaScript book has been carefully updated to cover JavaScript 1.5 (ECMAScript Version 3). The book also provides complete coverage of the W3C DOM standard (Level 1 and Level 2), while retaining material on the legacy Level 0 DOM for backward compatibility. * The Definitive Guide* is a complete programmer's guide and reference manual for JavaScript. It is particularly useful for developers working with the latest standards-compliant web browsers, such as Internet Explorer 6, Netscape 6, and Mozilla. HTML authors can learn how to use JavaScript to build dynamic web pages. Experienced programmers can quickly find the information they need to start writing sophisticated JavaScript programs. This book is an indispensable reference for all JavaScript programmers, regardless of experience level. ---------- *Description from the Fourth Edition (2007, O'Reilly Media)* Printing History August 1996 Beta Edition. January 1997 Second Edition. June 1998 Third Edition. January 2002 Fourth Edition. From the cover. JavaScript is the programming language of the web and is used by more software developers today than any other programming language. For nearly 25 years this best seller has been the go-to guide for JavaScript programmers, and this new edition has been fully updated to cover the 2020 version of JavaScript. You'll find engaging and illuminating example code throughout and new chapters covering classes, modules, iterators, generators, Promises, and async/await. This book is for programmers who want to learn JavaScript and web developers ready to take their understanding and mastery of the language to the next level. Topics include: types, variables, operators, statements, objects, and arrays; functions, classes, modules, iterators, generators, Promises, and async/await; JavaScript's standard library: data structures, regular expressions, JSON, internationalization, and URLs; the web platform: documents, components, graphics, networking, storage, and threads; Node.js: buffers, files, streams, threads, child processes, web clients, and web servers; tools and language extensions that professional JavaScript developers rely on JavaScript is the programming language of the web and is used by more software developers today than any other programming language. For nearly 25 years this best seller has been the go-to guide for JavaScript programmers, and this new edition has been fully updated to cover the 2020 version of JavaScript. You'll find engaging and illuminating example code throughout and new chapters covering classes, modules, iterators, generators, Promises, and async/await. This book is for programmers who want to learn JavaScript and web developers ready to take their understanding and mastery of the language to the next level. -- Provided by publisher "For web developers and other programmers interested in using JavaScript, this bestselling book provides the most comprehensive JavaScript material on the market. The seventh edition represents a significant update, with new information for ECMAScript 2020, and new chapters on language-specific features. The Definitive Guide is ideal for experienced programmers who want to learn the programming language of the web, and for current JavaScript programmers who want to master it."--Summary from descriptive page For Web Developers And Other Programmers Interested In Using Javascript, This Bestselling Book Provides The Most Comprehensive Javascript Reference Section On The Market. The Seventh Edition Represents A Significant Update, With New Material For Ecmascript 2017 (es8), And New Chapters On Language-specific Features. The Definitive Guide Is Ideal For Experienced Programmers Who Want To Learn The Programming Language Of The Web, And For Current Javascript Programmers Who Want To Master It. JavaScript是Web编程语言,也是如今软件开发者使用最多的编程语言。近25年来,这本畅销书一直是JavaScript程序员必读的技术著作,本版已经更新到涵盖JavaScript的2020版。新增的关于类、模块、迭代器、生成器、期约和async/await的章节中,令人深思、富有启发性的示例随处可见。 本书适合想学习JavaScript的程序员,以及希望深入理解和掌握这门语言的Web开发者。 本书涵盖以下内容: 类型、变量、操作符、语句、对象和数组。 函数、类、模块、迭代器、生成器、期约和async/await。 JavaScript标准库,包括数据结构、正则表达式、JSON、国际化和URL。 Web平台,包括文档、组件、图形、网络、存储和线程。 Node.js,包括缓冲区、文件、流、线程、子进程、Web客戶端和Web服务器。 专业JavaScript开发者必备的工具和语言扩展。