Then Came You: Forbidden age-gap romance

Now in its third edition, this bestselling guide to TypeScript takes you through the nuts and bolts of the language. No frills, no fuss—just TypeScript essentials! TypeScript enhances JavaScript with static typing, while keeping all the JS flexibility you know and love! It’s the perfect choice for any developer looking to improve the predictability and reliability of their code. Essential TypeScript 5, Third Edition teaches you how to get the most out of TypeScript 5 for a consistent, dependable development experience. Inside Essential TypeScript 5, Third Edition you’ll learn how to: Configure the TypeScript development tools Use type annotations Create strongly typed functions and classes Use generic types Use type guards to determine types Create and consume type declaration files Use TypeScript to create web applications with Angular and React The book starts you off with a proper understanding of the JavaScript type system that will make using TypeScript so much easier. On that solid foundation, you’ll build your understanding of TypeScript development, following a hands-on learning path all the way to TypeScript’s advanced features. About the technology TypeScript is a popular superset of JavaScript that adds support for static typing. TypeScript’s typing features, which will be instantly familiar to C# or Java programmers, help you reduce errors and improve the overall quality of your JavaScript code. About the book Essential TypeScript 5 is a fully updated third edition of the classic Adam Freeman bestseller. It provides full coverage of TypeScript 5, including new features like decorators. You’ll begin with the hows-and-whys of TypeScript, then quickly progress to practical applications of static types. No wasted pages! Each chapter is focused on the skills you need to write awesome web apps. What's inside Configure your development tools Create strongly typed functions and classes Use generic types, type annotations, and type guards Create and consume type declaration files About the reader For JavaScript developers. No previous experience with TypeScript required. About the author Adam Freeman has held senior positions in a range of companies, most recently serving as CTO and COO of a global bank. He has written 50 programming books. The technical editor on this book is Fabio Claudio Ferracchiati. Table of Contents 1 Understanding TypeScript Part 1 2 Your first TypeScript application 3 JavaScript primer, part 1 4 JavaScript primer, part 2 5 Using the TypeScript compiler 6 Testing and debugging TypeScript Part 2 7 Understanding static types 8 Using functions 9 Using arrays, tuples, and enums 10 Working with objects 11 Working with classes and interfaces 12 Using generic types 13 Advanced generic types 14 Using decorators 15 Working with JavaScript Part 3 16 Creating a stand-alone web app, part 1 17 Creating a stand-alone web app, part 2 18 Creating an Angular app, part 1 19 Creating an Angular app, part 2 20 Creating a React app 21 Creating a React app, part 2 Essential TypeScript 5, Third Edition dedication brief contents contents preface about this book Who should read this book How this book is organized: a roadmap About the code liveBook discussion forum about the author about the cover illustration 1 Understanding TypeScript 1.1 Should you use TypeScript? 1.1.1 Understanding the TypeScript developer productivity features 1.1.2 Understanding the JavaScript version features 1.2 What do you need to know? 1.3 How do you set up your development environment? 1.4 What Is the structure of this book? 1.5 Are there lots of examples? 1.6 Where can you get the example code? 1.7 What if you have problems following the examples? 1.7.1 What if you find an error in the book? 1.8 How do you contact the author? 1.9 What if you really enjoyed this book? 1.10 What if this book has made you angry? Summary Part 1 2 Your first TypeScript application 2.1 Getting ready for this book 2.1.1 Step 1: Install Node.js 2.1.2 Step 2: Install Git 2.1.3 Step 3: Install TypeScript 2.1.4 Step 4: Install a programmer’s editor 2.2 Creating the project 2.2.1 Initializing the project 2.2.2 Creating the compiler configuration file 2.2.3 Adding a TypeScript code file 2.2.4 Compiling and executing the code 2.2.5 Defining the data model 2.2.6 Adding features to the collection class 2.3 Using a third-party package 2.3.1 Preparing for the third-party package 2.3.2 Installing and using the third-party package 2.3.3 Adding type declarations for the JavaScript package 2.4 Adding commands 2.4.1 Filtering items 2.4.2 Adding tasks 2.4.3 Marking tasks complete 2.5 Persistently storing data Summary 3 JavaScript primer, part 1 3.1 Preparing for this chapter 3.2 Getting confused by JavaScript 3.3 Understanding JavaScript types 3.3.1 Working with primitive data types 3.3.2 Understanding type coercion 3.3.3 Working with functions 3.4 Working with arrays 3.4.1 Using the spread operator on arrays 3.4.2 Destructuring arrays 3.5 Working with objects 3.5.1 Adding, changing, and deleting object properties 3.5.2 Using the spread and rest operators on objects 3.5.3 Defining getters and setters 3.5.4 Defining methods 3.6 Understanding the this keyword 3.6.1 Understanding the this keyword in stand-alone functions 3.6.2 Understanding this in methods 3.6.3 Changing the behavior of the this keyword 3.6.4 Understanding this in arrow functions 3.6.5 Returning to the original problem Summary 4 JavaScript primer, part 2 4.1 Preparing for this chapter 4.2 Understanding JavaScript object inheritance 4.2.1 Inspecting and modifying an object’s prototype 4.2.2 Creating custom prototypes 4.2.3 Using constructor functions 4.2.4 Chaining constructor functions 4.2.5 Checking prototype types 4.2.6 Defining static properties and methods 4.2.7 Using JavaScript classes 4.3 Using iterators and generators 4.3.1 Using a generator 4.3.2 Defining iterable objects 4.4 Using JavaScript collections 4.4.1 Storing data by key using an object 4.4.2 Storing data by key using a map 4.4.3 Using symbols for map keys 4.4.4 Storing data by index 4.5 Using modules 4.5.1 Declaring the module type 4.5.2 Creating a JavaScript module 4.5.3 Using a JavaScript module 4.5.4 Exporting named features from a module 4.5.5 Defining multiple named features in a module Summary 5 Using the TypeScript compiler 5.1 Preparing for this chapter 5.2 Understanding the project structure 5.3 Using the Node Package Manager 5.4 Understanding the compiler configuration file 5.5 Compiling TypeScript code 5.5.1 Understanding compiler errors 5.5.2 Using watch mode and executing the compiled code 5.6 Using the version targeting feature 5.7 Setting the library files for compilation 5.8 Selecting a module format 5.8.1 Specifying a module format 5.9 Useful compiler configuration settings Summary 6 Testing and debugging TypeScript 6.1 Preparing for this chapter 6.2 Debugging TypeScript code 6.2.1 Preparing for debugging 6.2.2 Using Visual Studio Code for debugging 6.2.3 Using the integrated Node.js debugger 6.2.4 Using the remote Node.js debugging feature 6.3 Using the TypeScript linter 6.3.1 Disabling linting rules 6.4 Unit testing TypeScript 6.4.1 Configuring the test framework 6.4.2 Creating unit tests 6.4.3 Starting the test framework Summary Part 2 7 Understanding static types 7.1 Preparing for this chapter 7.2 Understanding static types 7.2.1 Creating a static type with a type annotation 7.2.2 Using implicitly defined static types 7.2.3 Using the any type 7.3 Using type unions 7.4 Using Type Assertions 7.4.1 Asserting to an unexpected type 7.5 Using a type guard 7.5.1 Understanding the never type 7.6 Using the unknown type 7.7 Using nullable types 7.7.1 Restricting nullable assignments 7.7.2 Removing null from a union with an assertion 7.7.3 Removing null from a union with a type guard 7.7.4 Using the definite assignment assertion Summary 8 Using functions 8.1 Preparing for this chapter 8.2 Defining functions 8.2.1 Redefining functions 8.2.2 Understanding function parameters 8.2.3 Understanding function results 8.2.4 Overloading function types 8.2.5 Understanding assert functions Summary 9 Using arrays, tuples, and enums 9.1 Preparing for this chapter 9.2 Working with arrays 9.2.1 Using inferred typing for arrays 9.2.2 Avoiding problems with inferred array types 9.2.3 Avoiding problems with empty arrays 9.3 Working with tuples 9.3.1 Processing tuples 9.3.2 Using tuple types 9.3.3 Using tuples with optional elements 9.3.4 Defining tuples with rest elements 9.4 Using enums 9.4.1 Understanding how enums work 9.4.2 Using string enums 9.4.3 Understanding the limitations of enums 9.5 Using literal value types 9.5.1 Using literal value types in functions 9.5.2 Mixing value types in a literal value type 9.5.3 Using overrides with literal value types 9.5.4 Using template literal string types 9.6 Using type aliases Summary 10 Working with objects 10.1 Preparing for this chapter 10.2 Working with objects 10.2.1 Using object shape type annotations 10.2.2 Understanding how shape types fit 10.2.3 Using type aliases for shape types 10.2.4 Using shape type unions 10.2.5 Understanding union property types 10.2.6 Using type guards for objects 10.3 Using type intersections 10.3.1 Using intersections for data correlation 10.3.2 Understanding intersection merging Summary 11 Working with classes and interfaces 11.1 Preparing for this chapter 11.2 Using constructor functions 11.3 Using classes 11.3.1 Using the access control keywords 11.3.2 Using JavaScript private fields 11.3.3 Defining read-only properties 11.3.4 Simplifying class constructors 11.3.5 Defining Accessors 11.3.6 Using auto-accessors 11.3.7 Using class inheritance 11.3.8 Using an abstract class 11.4 Using interfaces 11.4.1 Implementing multiple interfaces 11.4.2 Extending interfaces 11.4.3 Defining optional interface properties and methods 11.4.4 Defining an abstract interface implementation 11.4.5 Type guarding an interface 11.5 Dynamically creating properties 11.5.1 Enabling index value checking Summary 12 Using generic types 12.1 Preparing for this chapter 12.2 Understanding the problem solved by generic types 12.2.1 Adding support for another type 12.3 Creating generic classes 12.3.1 Understanding generic type arguments 12.3.2 Using different type arguments 12.3.3 Constraining generic type values 12.3.4 Defining multiple type parameters 12.3.5 Allowing the compiler to infer type arguments 12.3.6 Extending generic classes 12.3.7 Type guarding generic types 12.3.8 Defining a static method on a generic class 12.4 Defining generic interfaces 12.4.1 Extending generic interfaces 12.4.2 Implementing a generic interface Summary 13 Advanced generic types 13.1 Preparing for this chapter 13.2 Using generic collections 13.3 Using generic iterators 13.3.1 Combining an iterable and an iterator 13.3.2 Creating an iterable class 13.4 Using index types 13.4.1 Using the index type query 13.4.2 Explicitly providing generic type parameters for index types 13.4.3 Using the indexed access operator 13.4.4 Using an index type for the collection class 13.5 Using type mapping 13.5.1 Changing mapping names and types 13.5.2 Using a generic type parameter with a mapped type 13.5.3 Changing property optionality and mutability 13.5.4 Using the basic built-in mappings 13.5.5 Combining transformations in a single mapping 13.5.6 Creating types with a type mapping 13.6 Using conditional types 13.6.1 Nesting conditional types 13.6.2 Using conditional types in generic classes 13.6.3 Using conditional types with type unions 13.6.4 Using conditional types in type mappings 13.6.5 Identifying properties of a specific type 13.6.6 Inferring additional types in conditions Summary 14 Using decorators 14.1 Preparing for this chapter 14.2 Understanding decorators 14.2.1 Using decorator context data 14.2.2 Using specific types in a decorator 14.3 Using the other decorator types 14.3.1 Creating a class decorator 14.3.2 Creating a field decorator 14.3.3 Creating an accessor decorator 14.3.4 Creating an auto-accessor decorator 14.4 Passing an additional argument to a decorator 14.5 Applying multiple decorators 14.6 Using an initializer 14.7 Accumulating state data Summary 15 Working with JavaScript 15.1 Preparing for this chapter 15.1.1 Adding TypeScript code to the example project 15.2 Working with JavaScript 15.2.1 Including JavaScript in the compilation process 15.2.2 Type-checking JavaScript code 15.3 Describing types used in JavaScript code 15.3.1 Using comments to describe types 15.3.2 Using type declaration files 15.3.3 Describing third-party JavaScript code 15.3.4 Using Definitely Typed declaration files 15.3.5 Using packages that include type declarations 15.4 Generating declaration files Summary Part 3 16 Creating a stand-alone web app, part 1 16.1 Preparing for this chapter 16.2 Creating the toolchain 16.3 Adding a bundler 16.4 Adding a development web server 16.5 Creating the data model 16.5.1 Creating the data source 16.6 Rendering HTML content using the DOM API 16.6.1 Adding support for Bootstrap CSS styles 16.7 Using JSX to create HTML content 16.7.1 Understanding the JSX workflow 16.7.2 Configuring the compiler and the loader 16.7.3 Creating the factory function 16.7.4 Using the JSX class 16.7.5 Importing the factory function in the JSX class 16.8 Adding features to the application 16.8.1 Displaying a filtered list of products 16.8.2 Displaying content and handling updates Summary 17 Creating a stand-alone web app, part 2 17.1 Preparing for this chapter 17.2 Adding a web service 17.2.1 Incorporating the data source into the application 17.3 Completing the application 17.3.1 Adding a header class 17.3.2 Adding an order details class 17.3.3 Adding a confirmation class 17.3.4 Completing the application 17.4 Deploying the application 17.4.1 Adding the production HTTP server package 17.4.2 Creating the persistent data file 17.4.3 Creating the server 17.4.4 Using relative URLs for data requests 17.4.5 Building the application 17.4.6 Testing the production build 17.5 Containerizing the application 17.5.1 Installing Docker 17.5.2 Preparing the application 17.5.3 Creating the Docker container 17.5.4 Running the application Summary 18 Creating an Angular app, part 1 18.1 Preparing for this chapter 18.1.1 Configuring the web service 18.1.2 Configuring the Bootstrap CSS package 18.1.3 Starting the example application 18.2 Understanding TypeScript in Angular development 18.2.1 Understanding the TypeScript compiler configuration 18.3 Creating the data model 18.3.1 Creating the Data Source 18.3.2 Creating the data source implementation class 18.3.3 Configuring the data source 18.4 Displaying a filtered list of products 18.4.1 Displaying the category buttons 18.4.2 Creating the header display 18.4.3 Combining the components 18.5 Configuring the application Summary 19 Creating an Angular app, part 2 19.1 Preparing for this chapter 19.2 Completing the example application features 19.2.1 Adding the summary component 19.2.2 Creating the routing configuration 19.3 Deploying the application 19.3.1 Adding the production HTTP server package 19.3.2 Creating the persistent data file 19.3.3 Creating the server 19.3.4 Using relative URLs for data requests 19.3.5 Building the application 19.3.6 Testing the production build 19.4 Containerizing the application 19.4.1 Preparing the application 19.4.2 Creating the Docker container 19.4.3 Running the application Summary 20 Creating a React app 20.1 Preparing for this chapter 20.1.1 Configuring the web service 20.1.2 Installing the Bootstrap CSS package 20.1.3 Starting the example application 20.2 Understanding TypeScript in React development 20.3 Defining the entity types 20.4 Displaying a filtered list of products 20.4.1 Using a functional component and hooks 20.4.2 Displaying a list of categories and the header 20.4.3 Composing and testing the components 20.5 Creating the data store 20.5.1 Implementing the HTTP API clients Summary 21 Creating a React app, part 2 21.1 Preparing for this chapter 21.2 Configuring URL routing 21.3 Completing the example application features 21.3.1 Adding the confirmation component 21.3.2 Consuming the orders web service 21.3.3 Completing the application 21.4 Deploying the application 21.4.1 Adding the production HTTP server package 21.4.2 Creating the persistent data file 21.4.3 Creating the server 21.4.4 Using relative URLs for data requests 21.4.5 Building the application 21.4.6 Testing the production build 21.5 Containerizing the application 21.5.1 Preparing the application 21.5.2 Creating the Docker container 21.5.3 Running the application Summary index