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

Lambda expressions

Lambda expressions are just expressions that can be used to declare anonymous functions (functions without a name). Before the ES6 specification, the only way to assign a function as a value to a variable was to use a function expression:

const log = function(arg: any) { console.log(arg); };

The ES6 specification introduced the arrow function syntax:

const log = (arg: any) => console.log(arg);

Please refer to Chapter 2, Mastering Functions, Chapter 4, The Runtime – The Event Loop and the this Operator, and Chapter 5, The Runtime – Closures and Prototypes, to learn more about arrow functions and function expressions.