Introducing ReScript

This book serves as a succinct guide on ReScript, a functional language for building web applications. Using examples of ReScript language features along with explanations of fundamental concepts in functional programming, this book will show web developers with a background in JavaScript how to effectively use ReScript to its full potential.

In Introducing ReScript, you'll learn how to use features in ReScript that JavaScript lacks, such as type inference, null-safety, algebraic data types, pattern matching, and more. Along the way, you'll pick up functional programming concepts like immutability and higher-order functions. You'll also gain a sense of how ReScript works under the hood and how to leverage interoperability between ReScript and JavaScript.

Whether you're a web developer interested in dabbling with functional programming or you just want to learn how to write safer and cleaner code for web applications, this book is a great way for you to get started with ReScript.

WHAT YOU WILL LEARN

* Use ReScript to write clean, safe, and elegant software
* Understand the features of ReScript that set it apart from JavaScript, such as type inference, null-safety, and algebraic data types
* Explore functional programming concepts like immutabhigher-orderr order functions, and pattern matching
* Use popular JavaScript libraries and frameworks in your ReScript code and integrate ReScript code into JavaScript codebases

WHO THIS BOOK IS FOR

Web developers that want a strictly typed, safer alternative to JavaScript, as well as web developers interested in learning functional programming and leveraging the elegant and powerful functional features in ReScript.

Danny Yang is a professional software engineer at Meta working on infrastructure for WhatsApp. He has previously worked on Facebook Messenger, including the web interface which was written in ReScript. His technical interests include functional programming, compilers, and data visualization, which he writes about on his blog.

Chapter 1, Intro

Chapter Goal: Learn what functional programming is, and the background of the ReScript language

● What is ReScript?

● Why should you learn ReScript?

● What is functional programming?

● Why should you learn functional programming?Chapter 2, Basics

Chapter Goal: Learn the basic features of ReScript, like expressions and operators

- Development environment setup

- Hello, World in ReScript

- Expressions

- Operators

- If expressions

- Let expressions

- Printing and debugging

Chapter 3, Functions

Chapter Goal: learn how functions work in ReScript

- Defining a function

- Applying a function

- Polymorphic functions

- Anonymous functions

Chapter 4, Lists and Arrays

Chapter Goal: learn the data structures for ordered data in ReScript, learn about immutable data structures

- Building a list

- Accessing a list

- Mutating a list

- Arrays and mutability

- IterationChapter 5, Records and Objects

Chapter Goal: learn the ways to represent composite data types in ReScript

- Records

- Objects

Chapter 6, Pattern Matching and Destructuring

Chapter Goal: learn one of ReScript's most powerful features and how to work with the shape of your data

- Pattern matching/switch

- Destructuring with let

- Destructuring in functions

Chapter 7, Algebraic Data Types

Chapter Goal: learn how represent complex data in ReScript's type system

- Variants

- Polymorphic Variants

- Options- Tuples

Chapter 8, Higher Order Programming

Chapter Goal:

- Higher order functions

- Map

- Filter

- Reduce

- Generalizing to other data structures- Piping

- Currying

Chapter 9, Modules

Chapter Goal: Introduce modules in ReScript, and how they can be used for higher order programming

- What are modules

- Scope/visibility

- Signature

- Import/Export

- Functors

Chapter 10, Using ReScript in Production

Chapter Goal: learn about ReScript's interoperability with JavaScript

- Calling ReScript from JavaScript

- Calling JavaScript from ReScript

- Embedding JavaScript in ReScript

- Working with DOM

- Working with JSON

- Runtime representation