Understanding ECMAScript 6 by Zakas, Nicholas C. -- Read -- Imperial Library of Trantor

Index

Cover Page Title Page Copyright Page About the Author About the Technical Reviewer Brief Contents Contents in Detail Foreword Acknowledgments Introduction

The Road to ECMAScript 6 About This Book

Browser and Node.js Compatibility Who This Book Is For Overview Conventions Used Help and Support

Chapter 1: Block Bindings

var Declarations and Hoisting Block-Level Declarations

let Declarations No Redeclaration const Declarations The Temporal Dead Zone

Block Bindings in Loops

Functions in Loops let Declarations in Loops const Declarations in Loops

Global Block Bindings Emerging Best Practices for Block Bindings Summary

Chapter 2: Strings and Regular Expressions

Better Unicode Support

UTF-16 Code Points The codePointAt() Method The String.fromCodePoint() Method The normalize() Method The Regular Expression u Flag

Other String Changes

Methods for Identifying Substrings The repeat() Method

Other Regular Expression Changes

The Regular Expression y Flag Duplicating Regular Expressions The flags Property

Template Literals

Basic Syntax Multiline Strings Making Substitutions Tagged Templates

Summary

Chapter 3: Functions

Functions with Default Parameter Values

Simulating Default Parameter Values in ECMAScript 5 Default Parameter Values in ECMAScript 6 How Default Parameter Values Affect the arguments Object Default Parameter Expressions Default Parameter TDZ

Working with Unnamed Parameters

Unnamed Parameters in ECMAScript 5 Rest Parameters

Increased Capabilities of the Function Constructor The Spread Operator The name Property

Choosing Appropriate Names Special Cases of the name Property

Clarifying the Dual Purpose of Functions

Determining How a Function Was Called in ECMAScript 5 The new.target Metaproperty

Block-Level Functions

Deciding When to Use Block-Level Functions Block-Level Functions in Non-Strict Mode

Arrow Functions

Arrow Function Syntax Creating Immediately Invoked Function Expressions No this Binding Arrow Functions and Arrays No arguments Binding Identifying Arrow Functions

Tail Call Optimization

How Tail Calls Are Different in ECMAScript 6 How to Harness Tail Call Optimization

Summary

Chapter 4: Expanded Object Functionality

Object Categories Object Literal Syntax Extensions

Property Initializer Shorthand Concise Methods Computed Property Names

New Methods

The Object.is() Method The Object.assign() Method

Duplicate Object Literal Properties Own Property Enumeration Order Enhancements for Prototypes

Changing an Object’s Prototype Easy Prototype Access with Super References

A Formal Method Definition Summary

Chapter 5: Destructuring for Easier Data Access

Why Is Destructuring Useful? Object Destructuring

Destructuring Assignment Default Values Assigning to Different Local Variable Names Nested Object Destructuring

Array Destructuring

Destructuring Assignment Default Values Nested Array Destructuring Rest Items

Mixed Destructuring Destructured Parameters

Destructured Parameters Are Required Default Values for Destructured Parameters

Summary

Chapter 6: Symbols and Symbol Properties

Creating Symbols Using Symbols Sharing Symbols Symbol Coercion Retrieving Symbol Properties Exposing Internal Operations with Well-Known Symbols

The Symbol.hasInstance Method The Symbol.isConcatSpreadable Property The Symbol.match, Symbol.replace, Symbol.search, and Symbol.split Properties The Symbol.toPrimitive Method The Symbol.toStringTag Property The Symbol.unscopables Property

Summary

Chapter 7: Sets and Maps

Sets and Maps in ECMAScript 5 Problems with Workarounds Sets in ECMAScript 6

Creating Sets and Adding Items Removing Items The forEach() Method for Sets Converting a Set to an Array Weak Sets

Maps in ECMAScript 6

Map Methods Map Initialization The forEach() Method for Maps Weak Maps

Summary

Chapter 8: Iterators and Generators

The Loop Problem What Are Iterators? What Are Generators?

Generator Function Expressions Generator Object Methods

Iterables and for-of Loops

Accessing the Default Iterator Creating Iterables

Built-In Iterators

Collection Iterators String Iterators NodeList Iterators

The Spread Operator and Nonarray Iterables Advanced Iterator Functionality

Passing Arguments to Iterators Throwing Errors in Iterators Generator Return Statements Delegating Generators

Asynchronous Task Running

A Simple Task Runner Task Running with Data An Asynchronous Task Runner

Summary

Chapter 9: Introducing JavaScript Classes

Class-Like Structures in ECMAScript 5 Class Declarations

A Basic Class Declaration Why Use the Class Syntax?

Class Expressions

A Basic Class Expression Named Class Expressions

Classes as First-Class Citizens Accessor Properties Computed Member Names Generator Methods Static Members Inheritance with Derived Classes

Shadowing Class Methods Inherited Static Members Derived Classes from Expressions Inheriting from Built-Ins The Symbol.species Property

Using new.target in Class Constructors Summary

Chapter 10: Improved Array Capabilities

Creating Arrays

The Array.of() Method The Array.from() Method

New Methods on All Arrays

The find() and findIndex() Methods The fill() Method The copyWithin() Method

Typed Arrays

Numeric Data Types Array Buffers Manipulating Array Buffers with Views

Similarities Between Typed and Regular Arrays

Common Methods The Same Iterators The of() and from() Methods

Differences Between Typed and Regular Arrays

Behavioral Differences Missing Methods Additional Methods

Summary

Chapter 11: Promises and Asynchronous Programming

Asynchronous Programming Background

The Event Model The Callback Pattern

Promise Basics

The Promise Life Cycle Creating Unsettled Promises Creating Settled Promises Executor Errors

Global Promise Rejection Handling

Node.js Rejection Handling Browser Rejection Handling

Chaining Promises

Catching Errors Returning Values in Promise Chains Returning Promises in Promise Chains

Responding to Multiple Promises

The Promise.all() Method The Promise.race() Method

Inheriting from Promises Promise-Based Asynchronous Task Running Summary

Chapter 12: Proxies and the Reflection API

The Array Problem Introducing Proxies and Reflection Creating a Simple Proxy Validating Properties Using the set Trap Object Shape Validation Using the get Trap Hiding Property Existence Using the has Trap Preventing Property Deletion with the deleteProperty Trap Prototype Proxy Traps

How Prototype Proxy Traps Work Why Two Sets of Methods?

Object Extensibility Traps

Two Basic Examples Duplicate Extensibility Methods

Property Descriptor Traps

Blocking Object.defineProperty() Descriptor Object Restrictions Duplicate Descriptor Methods

The ownKeys Trap Function Proxies with the apply and construct Traps

Validating Function Parameters Calling Constructors Without new Overriding Abstract Base Class Constructors Callable Class Constructors

Revocable Proxies Solving the Array Problem

Detecting Array Indexes Increasing length When Adding New Elements Deleting Elements When Reducing length Implementing the MyArray Class

Using a Proxy as a Prototype

Using the get Trap on a Prototype Using the set Trap on a Prototype Using the has Trap on a Prototype Proxies as Prototypes on Classes

Summary

Chapter 13: Encapsulating Code with Modules

What Are Modules? Basic Exporting Basic Importing

Importing a Single Binding Importing Multiple Bindings Importing an Entire Module A Subtle Quirk of Imported Bindings

Renaming Exports and Imports Default Values in Modules

Exporting Default Values Importing Default Values

Re-exporting a Binding Importing Without Bindings Loading Modules

Using Modules in Web Browsers Browser Module Specifier Resolution

Summary

Appendix A: Minor Changes in ECMAScript 6

Working with Integers

Identifying Integers Safe Integers

New Math Methods Unicode Identifiers Formalizing the __proto__ Property

Appendix B: Understanding ECMAScript 7 (2016)

The Exponentiation Operator

Order of Operations Operand Restriction

The Array.prototype.includes() Method

How to Use Array.prototype.includes() Value Comparison

A Change to Function-Scoped Strict Mode

Index The Electronic Frontier Foundation (EFF) Updates Level Up Your JavaScript

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