book

JavaScript

Name: JavaScript
ISBN: 9781836642237

by Rheinwerk Publishing, Inc, Philip Ackermann

September 2024

Beginner to intermediate

985 pages

35h 37m

English

Packt Publishing

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Dear Reader
Notes on Usage
Table of Contents
Book Resources
Preface
Target Audience Structure of the Book How Should I Read This Book? Acknowledgments
1 Basics and Introduction
1.1 Programming Basics1.1.1 Communicating with the Computer1.1.2 Programming Languages1.1.3 Tools for Program Design
1.2 Introduction to JavaScript
1.2.1 History1.2.2 Fields of Application
1.3 Summary
2 Getting Started
2.1 Introduction to JavaScript and Web Development2.1.1 The Relationship among HTML, CSS, and JavaScript2.1.2 The Right Tool for Development
2.2 Integrating JavaScript into a Web Page
2.2.1 Preparing a Suitable Folder Structure2.2.2 Creating a JavaScript File2.2.3 Embedding a JavaScript File in an HTML File2.2.4 Defining JavaScript Directly within the HTML2.2.5 Placement and Execution of the <script> Elements2.2.6 Displaying the Source Code

2.3 Creating Output
2.3.1 Showing the Standard Dialog Window2.3.2 Writing to the Console2.3.3 Using Existing UI Components
2.4 Summary
3 Language Core
3.1 Storing Values in Variables3.1.1 Defining Variables3.1.2 Using Valid Variable Names3.1.3 Defining Constants
3.2 Using the Different Data Types
3.2.1 Numbers3.2.2 Strings3.2.3 Boolean Values3.2.4 Arrays3.2.5 Objects3.2.6 Special Data Types3.2.7 Symbols
3.3 Deploying the Different Operators
3.3.1 Operators for Working with Numbers3.3.2 Operators for Easier Assignment3.3.3 Operators for Working with Strings3.3.4 Operators for Working with Boolean Values3.3.5 Operators for Working with Bits3.3.6 Operators for Comparing Values3.3.7 The Optional Chaining Operator3.3.8 The Logical Assignment Operators3.3.9 Operators for Special Operations
3.4 Controlling the Flow of a Program
3.4.1 Defining Conditional Statements3.4.2 Defining Branches3.4.3 Using the Selection Operator3.4.4 Defining Multiway Branches3.4.5 Defining Counting Loops3.4.6 Defining Head-Controlled Loops3.4.7 Defining Tail-Controlled Loops3.4.8 Prematurely Terminating Loops and Loop Iterations
3.5 Creating Reusable Code Blocks
3.5.1 Defining Functions3.5.2 Calling Functions3.5.3 Passing and Evaluating Function Parameters3.5.4 Defining Return Values3.5.5 Defining Default Values for Parameters3.5.6 Using Elements from an Array as Parameters3.5.7 Defining Functions Using Short Notation3.5.8 Modifying Strings via Functions3.5.9 Functions in Detail3.5.10 Calling Functions through User Interaction
3.6 Responding to Errors and Handling Them Correctly
3.6.1 Syntax Errors3.6.2 Runtime Errors3.6.3 Logic Errors3.6.4 The Principle of Error Handling3.6.5 Catching and Handling Errors3.6.6 Triggering Errors3.6.7 Errors and the Function Call Stack3.6.8 Calling Certain Statements Regardless of Errors That Have Occurred
3.7 Commenting the Source Code
3.8 Debugging the Code
3.8.1 Introduction3.8.2 A Simple Code Example3.8.3 Defining Breakpoints3.8.4 Viewing Variable Assignments3.8.5 Running a Program Step by Step3.8.6 Defining Multiple Breakpoints3.8.7 Other Types of Breakpoints3.8.8 Viewing the Function Call Stack
3.9 Summary
4 Working with Reference Types
4.1 Difference between Primitive Data Types and Reference Types4.1.1 The Principle of Primitive Data Types4.1.2 The Principle of Reference Types4.1.3 Primitive Data Types and Reference Types as Function Arguments4.1.4 Determining the Type of a Variable4.1.5 Outlook
4.2 Encapsulating State and Behavior in Objects
4.2.1 Introduction to Object-Oriented Programming4.2.2 Creating Objects Using Literal Notation4.2.3 Creating Objects via Constructor Functions4.2.4 Creating Objects Using Classes4.2.5 Creating Objects via the Object.create() Function4.2.6 Accessing Properties and Calling Methods4.2.7 Adding or Overwriting Object Properties and Object Methods4.2.8 Deleting Object Properties and Object Methods4.2.9 Outputting Object Properties and Object Methods4.2.10 Using Symbols to Define Unique Object Properties4.2.11 Preventing Changes to Objects
4.3 Working with Arrays
4.3.1 Creating and Initializing Arrays4.3.2 Accessing Elements of an Array4.3.3 Adding Elements to an Array4.3.4 Removing Elements from an Array4.3.5 Copying Some of the Elements from an Array4.3.6 Sorting Arrays4.3.7 Using Arrays as a Stack4.3.8 Using Arrays as a Queue4.3.9 Finding Elements in Arrays4.3.10 Copying Elements within an Array4.3.11 Converting Arrays to Strings
4.4 Extracting Values from Arrays and Objects
4.4.1 Extracting Values from Arrays4.4.2 Extracting Values from Objects4.4.3 Extracting Values within a Loop4.4.4 Extracting Arguments of a Function4.4.5 Copying Object Properties to Another Object4.4.6 Copying Object Properties from Another Object
4.5 Working with Strings
4.5.1 The Structure of a String4.5.2 Determining the Length of a String4.5.3 Searching within a String4.5.4 Extracting Parts of a String
4.6 Using Maps
4.6.1 Creating Maps4.6.2 Basic Operations4.6.3 Iterating over Maps4.6.4 Using Weak Maps
4.7 Using Sets
4.7.1 Creating Sets4.7.2 Basic Operations of Sets4.7.3 Iterating over Sets4.7.4 Using Weak Sets
4.8 Other Global Objects
4.8.1 Working with Date and Time Information4.8.2 Performing Complex Calculations4.8.3 Wrapper Objects for Primitive Data Types
4.9 Working with Regular Expressions
4.9.1 Defining Regular Expressions4.9.2 Testing Characters against a Regular Expression4.9.3 Using Character Classes4.9.4 Limiting Beginning and End4.9.5 Using Quantifiers4.9.6 Searching for Occurrences4.9.7 Searching All Occurrences within a String4.9.8 Accessing Individual Parts of an Occurrence4.9.9 Searching for Specific Strings4.9.10 Replacing Occurrences within a String4.9.11 Searching for Occurrences4.9.12 Splitting Strings
4.10 Functions as Reference Types
4.10.1 Using Functions as Arguments4.10.2 Using Functions as Return Values4.10.3 Standard Methods of Each Function
4.11 Summary
5 Dynamically Changing Web Pages
5.1 Structure of a Web Page5.1.1 Document Object Model5.1.2 The Different Types of Nodes5.1.3 The Document Node
5.2 Selecting Elements
5.2.1 Selecting Elements by ID5.2.2 Selecting Elements by Class5.2.3 Selecting Elements by Element Name5.2.4 Selecting Elements by Name5.2.5 Selecting Elements by Selector5.2.6 Selecting the Parent Element of an Element5.2.7 Selecting the Child Elements of an Element5.2.8 Selecting the Sibling Elements of an Element5.2.9 Calling Selection Methods on Elements5.2.10 Selecting Elements by Type
5.3 Working with Text Nodes
5.3.1 Accessing the Text Content of an Element5.3.2 Modifying the Text Content of an Element5.3.3 Modifying the HTML below an Element5.3.4 Creating and Adding Text Nodes
5.4 Working with Elements
5.4.1 Creating and Adding Elements5.4.2 Removing Elements and Nodes5.4.3 The Different Types of HTML Elements
5.5 Working with Attributes
5.5.1 Reading the Value of an Attribute5.5.2 Changing the Value of an Attribute or Adding a New Attribute5.5.3 Creating and Adding Attribute Nodes5.5.4 Removing Attributes5.5.5 Accessing CSS classes
5.6 Summary
6 Processing and Triggering Events
6.1 The Concept of Event-Driven Programming
6.2 Responding to Events
6.2.1 Defining an Event Handler via HTML6.2.2 Defining an Event Handler via JavaScript6.2.3 Defining Event Listeners6.2.4 Defining Multiple Event Listeners6.2.5 Passing Arguments to Event Listeners6.2.6 Removing Event Listeners6.2.7 Defining Event Handlers and Event Listeners via a Helper Function6.2.8 Accessing Information of an Event
6.3 The Different Types of Events
6.3.1 Events when Interacting with the Mouse6.3.2 Events when Interacting with the Keyboard and with Text Fields6.3.3 Events when Working with Forms6.3.4 Events when Focusing Elements6.3.5 General Events of the User Interface6.3.6 Events on Mobile Devices
6.4 Understanding and Influencing the Flow of Events
6.4.1 The Event Phases6.4.2 Interrupting the Event Flow6.4.3 Preventing Default Actions of Events
6.5 Programmatically Triggering Events
6.5.1 Triggering Simple Events6.5.2 Triggering Events with Passed Arguments6.5.3 Triggering Default Events
6.6 Summary
7 Working with Forms
7.1 Accessing Forms and Form Fields7.1.1 Accessing Forms7.1.2 Accessing Form Elements7.1.3 Reading the Value of Text Fields and Password Fields7.1.4 Reading the Value of Checkboxes7.1.5 Reading the Value of Radio Buttons7.1.6 Reading the Value of Selection Lists7.1.7 Reading the Values of Multiple Selection Lists7.1.8 Populating Selection Lists with Values Using JavaScript
7.2 Programmatically Submitting and Resetting Forms
7.3 Validating Form Inputs
7.4 Summary
8 Controlling Browsers and Reading Browser Information
8.1 The Browser Object Model
8.2 Accessing Window Information
8.2.1 Determining the Size and Position of a Browser Window8.2.2 Changing the Size and Position of a Browser Window8.2.3 Accessing Display Information of the Browser Bars8.2.4 Determining General Properties8.2.5 Opening New Browser Windows8.2.6 Closing the Browser Window8.2.7 Opening Dialogs8.2.8 Executing Functions in a Time-Controlled Manner
8.3 Accessing Navigation Information of a Currently Open Web Page
8.3.1 Accessing the Individual Components of the URL8.3.2 Accessing Query String Parameters8.3.3 Loading a New Web Page
8.4 Viewing and Modifying the Browsing History
8.4.1 Navigating in the Browsing History8.4.2 Browsing History for Single-Page Applications8.4.3 Adding Entries to the Browsing History8.4.4 Responding to Changes in the Browsing History8.4.5 Replacing the Current Entry in the Browsing History
8.5 Recognizing Browsers and Determining Browser Features
8.6 Accessing Screen Information
8.7 Summary
9 Dynamically Reloading Contents of a Web Page
9.1 The Principle of Ajax9.1.1 Synchronous Communication9.1.2 Asynchronous Communication9.1.3 Typical Use Cases for Ajax9.1.4 Data Formats Used
9.2 The XML Format
9.2.1 The Structure of XML9.2.2 XML and the DOM API9.2.3 Converting Strings to XML Objects9.2.4 Converting XML Objects to Strings
9.3 The JSON Format
9.3.1 The Structure of JSON9.3.2 Difference between JSON and JavaScript Objects9.3.3 Converting Objects to JSON Format9.3.4 Converting Objects from JSON Format
9.4 Making Requests via Ajax
9.4.1 The XMLHttpRequest Object9.4.2 Loading HTML Data via Ajax9.4.3 Loading XML Data via Ajax9.4.4 Loading JSON Data via Ajax9.4.5 Sending Data to the Server via Ajax9.4.6 Submitting Dorms via Ajax9.4.7 Loading Data from Other Domains9.4.8 The Newer Alternative to XMLHttpRequest: The Fetch API
9.5 Summary
10 Simplifying Tasks with jQuery
10.1 Introduction10.1.1 Embedding jQuery10.1.2 Embedding jQuery via a Content Delivery Network10.1.3 Using jQuery10.1.4 Simplifying Tasks with jQuery
10.2 Working with the DOM
10.2.1 Selecting Elements10.2.2 Accessing and Modifying Content10.2.3 Filtering Selected Elements10.2.4 Accessing Attributes10.2.5 Accessing CSS Properties10.2.6 Navigating between Elements10.2.7 Using Effects and Animations
10.3 Responding to Events
10.3.1 Registering Event Listeners10.3.2 Responding to General Events10.3.3 Responding to Mouse Events10.3.4 Responding to Keyboard Events10.3.5 Responding to Form Events10.3.6 Accessing Information from Events
10.4 Creating Ajax Requests
10.4.1 Creating Ajax Requests10.4.2 Responding to Events10.4.3 Loading HTML Data via Ajax10.4.4 Loading XML Data via Ajax10.4.5 Loading JSON Data via Ajax
10.5 Summary
11 Dynamically Creating Images and Graphics
11.1 Drawing Images11.1.1 The Drawing Area11.1.2 The Rendering Context11.1.3 Drawing Rectangles11.1.4 Using Paths11.1.5 Drawing Texts11.1.6 Drawing Gradients11.1.7 Saving and Restoring the Canvas State11.1.8 Using Transformations11.1.9 Creating Animations
11.2 Integrating Vector Graphics
11.2.1 The SVG Format11.2.2 Integrating SVG in HTML11.2.3 Changing the Appearance of SVG Elements with CSS11.2.4 Manipulating the Behavior of SVG Elements via JavaScript
11.3 Summary
12 Using Modern Web APIs
12.1 Communicating via JavaScript12.1.1 Unidirectional Communication with the Server12.1.2 Bidirectional Communication with a Server12.1.3 Outgoing Communication from the Server
12.2 Recognizing Users
12.2.1 Using Cookies12.2.2 Creating Cookies12.2.3 Reading Cookies12.2.4 Example: Shopping Cart Based on Cookies12.2.5 Disadvantages of Cookies
12.3 Using the Browser Storage
12.3.1 Storing Values in the Browser Storage12.3.2 Reading Values from the Browser Storage12.3.3 Updating Values in the Browser Storage12.3.4 Deleting Values from the Browser Storage12.3.5 Responding to Changes in the Browser Storage12.3.6 The Different Types of Browser Storage12.3.7 Example: Shopping Cart Based on the Browser Storage
12.4 Using the Browser Database
12.4.1 Opening a Database12.4.2 Creating a Database12.4.3 Creating an Object Store12.4.4 Adding Objects to an Object Store12.4.5 Reading Objects from an Object Store12.4.6 Deleting Objects from an Object Store12.4.7 Updating Objects in an Object Store12.4.8 Using a Cursor
12.5 Accessing the File System
12.5.1 Selecting Files via File Dialog12.5.2 Selecting Files via Drag and Drop12.5.3 Reading Files12.5.4 Monitoring the Reading Progress
12.6 Moving Components of a Web Page
12.6.1 Events of a Drag-and-Drop Operation12.6.2 Defining Movable Elements12.6.3 Moving Elements
12.7 Parallelizing Tasks
12.7.1 The Principle of Web Workers12.7.2 Use Web Workers
12.8 Determining the Location of Users
12.8.1 Accessing Location Information12.8.2 Continuously Accessing Location Information12.8.3 Showing the Position on a Map12.8.4 Showing Directions
12.9 Reading the Battery Level of an End Device
12.9.1 Accessing Battery Information12.9.2 Responding to Events
12.10 Outputting Speech and Recognizing Speech
12.10.1 Outputting Speech12.10.2 Recognizing Speech
12.11 Creating Animations
12.11.1 Using the API12.11.2 Controlling an Animation
12.12 Working with the Command Line
12.12.1 Selecting and Inspecting DOM Elements12.12.2 Events Analysis12.12.3 Debugging, Monitoring, and Profiling
12.13 Developing Multilingual Applications
12.13.1 Explanation of Terms12.13.2 The Internationalization API12.13.3 Comparing Character String Expressions12.13.4 Formatting Dates and Times12.13.5 Formatting Numeric Values
12.14 Overview of Various Web APIs
12.15 Summary
13 Object-Oriented Programming
13.1 The Principles of Object-Oriented Programming13.1.1 Classes, Object Instances, and Prototypes13.1.2 Principle 1: Define Abstract Behavior13.1.3 Principle 2: Encapsulate Condition and Behavior13.1.4 Principle 3: Inherit Condition and Behavior13.1.5 Principle 4: Accept Different Types13.1.6 JavaScript and Object Orientation
13.2 Prototypical Object Orientation
13.2.1 The Concept of Prototypes13.2.2 Deriving from Objects13.2.3 Inheriting Methods and Properties13.2.4 Defining Methods and Properties in the Inheriting Object13.2.5 Overwriting Methods13.2.6 The Prototype Chain13.2.7 Calling Methods of the Prototype13.2.8 Prototypical Object Orientation and the Principles of Object Orientation
13.3 Pseudoclassical Object Orientation
13.3.1 Defining Constructor Functions13.3.2 Creating Object Instances13.3.3 Defining Methods13.3.4 Deriving from Objects13.3.5 Calling the Constructor of the "Superclass"13.3.6 Overwriting Methods13.3.7 Calling Methods of the "Superclass"13.3.8 Pseudoclassical Object Orientation and the Principles of Object Orientation
13.4 Object Orientation with Class Syntax
13.4.1 Defining Classes13.4.2 Creating Object Instances13.4.3 Defining Getters and Setters13.4.4 Defining Private Properties and Private Methods13.4.5 Deriving from "Classes"13.4.6 Overwriting Methods13.4.7 Calling Methods of the "Superclass"13.4.8 Defining Static Methods13.4.9 Defining Static Properties13.4.10 Class Syntax and the Principles of Object Orientation
13.5 Summary
14 Functional Programming
14.1 Principles of Functional Programming
14.2 Imperative Programming and Functional Programming
14.2.1 Iterating with the forEach() Method14.2.2 Mapping Values with the map() Method14.2.3 Filtering Values with the filter() Method14.2.4 Reducing Multiple Values to One Value with the reduce() Method14.2.5 Combination of the Different Methods
14.3 Summary
15 Correctly Structuring the Source Code
15.1 Avoiding Name Conflicts
15.2 Defining and Using Modules
15.2.1 The Module Design Pattern15.2.2 The Revealing Module Design Pattern15.2.3 AMD15.2.4 CommonJS15.2.5 Native Modules
15.3 Summary
16 Using Asynchronous Programming and Other Advanced Features
16.1 Understanding and Using Asynchronous Programming16.1.1 Using the Callback Design Pattern16.1.2 Using Promises16.1.3 Using Async Functions
16.2 Encapsulating Iteration over Data Structures
16.2.1 The Principle of Iterators16.2.2 Using Iterators16.2.3 Creating Your Own Iterator16.2.4 Creating an Iterable Object16.2.5 Iterating over Iterable Objects
16.3 Pausing and Resuming Functions
16.3.1 Creating a Generator Function16.3.2 Creating a Generator16.3.3 Iterating over Generators16.3.4 Creating Infinite Generators16.3.5 Controlling Generators with Parameters
16.4 Intercepting Access to Objects
16.4.1 The Principle of Proxies16.4.2 Creating Proxies16.4.3 Defining Handlers for Proxies
16.5 Summary
17 Creating Server-Based Applications with Node.js
17.1 Introduction to Node.js17.1.1 The Architecture of Node.js17.1.2 Installing Node.js17.1.3 A Simple Application
17.2 Managing Node.js Packages
17.2.1 Installing the Node.js Package Manager17.2.2 Installing Packages17.2.3 Creating Your Own Packages
17.3 Processing and Triggering Events
17.3.1 Triggering and Intercepting an Event17.3.2 Triggering an Event Multiple Times17.3.3 Intercepting an Event Exactly Once17.3.4 Intercepting an Event Multiple Times
17.4 Accessing the File System
17.4.1 Reading Files17.4.2 Writing Files17.4.3 Reading File Information17.4.4 Deleting Files17.4.5 Working with Directories
17.5 Creating a Web Server
17.5.1 Starting a Web Server17.5.2 Making Files Available via Web Server17.5.3 Creating a Client for a Web Server17.5.4 Defining Routes17.5.5 Using the Express.js Web Framework
17.6 Accessing Databases
17.6.1 MongoDB Installation17.6.2 Installing a MongoDB Driver for Node.js17.6.3 Establishing a Connection to the Database17.6.4 Creating a Collection17.6.5 Saving Objects17.6.6 Reading Objects17.6.7 Updating Objects17.6.8 Deleting Objects
17.7 Working with Streams
17.7.1 Introduction and Types of Streams17.7.2 Stream Use Cases17.7.3 Reading Data with Streams17.7.4 Writing Data with Streams17.7.5 Combining Streams Using Piping17.7.6 Error Handling during Piping
17.8 Summary
18 Creating Mobile Applications with JavaScript
18.1 The Different Types of Mobile Applications18.1.1 Native Applications18.1.2 Mobile Web Applications18.1.3 Hybrid Applications18.1.4 Comparison of the Different Approaches
18.2 Creating Mobile Applications with React Native
18.2.1 The Principle of React Native18.2.2 Installation and Project Initialization18.2.3 Starting the Application18.2.4 The Basic Structure of a React Native Application18.2.5 Using UI Components18.2.6 Communication with the Server18.2.7 Building and Publishing Applications
18.3 Summary
19 Desktop Applications with JavaScript
19.1 NW.js19.1.1 Installing and Creating an Application19.1.2 Starting the Application19.1.3 Packaging of the Application19.1.4 More Sample Applications
19.2 Electron
19.2.1 Installing and Creating an Application19.2.2 Starting the Application19.2.3 Packaging19.2.4 More Sample Applications
19.3 Summary
20 Controlling Microcontrollers with JavaScript
20.1 Espruino20.1.1 Technical Information20.1.2 Connection and Installation20.1.3 First Example20.1.4 Controlling LEDs20.1.5 More Modules20.1.6 Reading Sensors
20.2 Tessel
20.2.1 Technical Information20.2.2 Connection and Installation20.2.3 Controlling LEDs20.2.4 Programming the Push Buttons20.2.5 Extending the Tessel with Modules
20.3 BeagleBone Black
20.3.1 Technical Information20.3.2 Connection and Installation20.3.3 Controlling LEDs
20.4 Arduino
20.4.1 The Firmata Protocol20.4.2 Connection and Installation20.4.3 The Johnny Five Node.js Module
20.5 Cylon.js
20.5.1 Controlling the BeagleBone Black with Cylon.js20.5.2 Controlling the Tessel Board with Cylon.js20.5.3 Controlling an Arduino with Cylon.js
20.6 Summary
21 Establishing a Professional Development Process
21.1 Automating Tasks21.1.1 Automating Tasks with Grunt21.1.2 Automating Tasks with Gulp
21.2 Automated Testing of Source Code
21.2.1 The Principle of Automated Tests21.2.2 The Principle of Test-Driven Development21.2.3 Automated Testing of Source Code with QUnit21.2.4 Automated Testing of Source Code with mocha
21.3 Source Code Version Management
21.3.1 Introduction to Version Management21.3.2 Installing and Configuring the Git Version Control System21.3.3 Creating a New Local Repository21.3.4 Cloning an Existing Repository21.3.5 Transferring Changes to the Staging Area21.3.6 Transferring Changes to the Local Repository21.3.7 The Different States in Git21.3.8 Transfering Changes to the Remote Repository21.3.9 Transferring Changes from the Remote Repository21.3.10 Working in a New Branch21.3.11 Adopting Changes from a Branch21.3.12 Overview of the Most Important Commands and Terms
21.4 Summary
A The Author
Index
Service Pages
Legal Notes

Content preview from JavaScript

14.2 Imperative Programming and Functional Programming

In this section, we’ll show you the advantages of functional programming compared to imperative programming. To do this, we'll introduce four methods available to arrays in JavaScript:

The forEach() method for iterating over arrays (which we discussed in Chapter 4)
The map() method for mapping elements of one array to new elements in another array
The filter() method for filtering elements in an array
The reduce() method for reducing the elements of an array to a single value

14.2.1 Iterating with the forEach() Method

If you want to iterate via an array or a list, you have several (imperative) options, which you’ve already learned about in this book (for example, in Chapter 3 ...

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ISBN: 9781836642237

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JavaScript

by Rheinwerk Publishing, Inc, Philip Ackermann

14.2 Imperative Programming and Functional Programming

14.2.1 Iterating with the forEach() Method

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