Book Image

Hands-On Functional Programming with TypeScript

By : Remo H. Jansen
Book Image

Hands-On Functional Programming with TypeScript

By: Remo H. Jansen

Overview of this book

Functional programming is a powerful programming paradigm that can help you to write better code. However, learning functional programming can be complicated, and the existing literature is often too complex for beginners. This book is an approachable introduction to functional programming and reactive programming with TypeScript for readers without previous experience in functional programming with JavaScript, TypeScript , or any other programming language. The book will help you understand the pros, cons, and core principles of functional programming in TypeScript. It will explain higher order functions, referential transparency, functional composition, and monads with the help of effective code examples. Using TypeScript as a functional programming language, you’ll also be able to brush up on your knowledge of applying functional programming techniques, including currying, laziness, and immutability, to real-world scenarios. By the end of this book, you will be confident when it comes to using core functional and reactive programming techniques to help you build effective applications with TypeScript.
Table of Contents (14 chapters)
5
The Runtime – Closures and Prototypes

Generators

If we invoke a function in TypeScript, we can assume that, once the function starts running, it will always run to completion before any other code can run. However, one type of function known as a generator can may be paused in the middle of execution—once or many times—and resumed later, allowing other code to run during these paused periods.

A generator represents a sequence of values. The interface of a generator object is just an iterator. An iterator implements the following interface:

interface Iterator<T> {
next(value?: any): IteratorResult<T>;
return?(value?: any): IteratorResult<T>;
throw?(e?: any): IteratorResult<T>;
}

The next function can be invoked until it runs out of values. We can define a generator by using the function keyword, followed by an asterisk, (*). The yield keyword is used to stop the execution of...