Book Image

ReasonML Quick Start Guide

By : Raphael Rafatpanah, Bruno Joseph D'mello
Book Image

ReasonML Quick Start Guide

By: Raphael Rafatpanah, Bruno Joseph D'mello

Overview of this book

ReasonML, also known as Reason, is a new syntax and toolchain for OCaml that was created by Facebook and is meant to be approachable for web developers. Although OCaml has several resources, most of them are from the perspective of systems development. This book, alternatively, explores Reason from the perspective of web development. You'll learn how to use Reason to build safer, simpler React applications and why you would want to do so. Reason supports immutability by default, which works quite well in the context of React. In learning Reason, you will also learn about its ecosystem – BuckleScript, JavaScript interoperability, and various npm workflows. We learn by building a real-world app shell, including a client-side router with page transitions, that we can customize for any Reason project. You'll learn how to leverage OCaml's excellent type system to enforce guarantees about business logic, as well as preventing runtime type errors.You'll also see how the type system can help offload concerns that we once had to keep in our heads. We'll explore using CSS-in-Reason, how to use external JSON in Reason, and how to unit-test critical business logic. By the end of the book, you'll understand why Reason is exploding in popularity and will have a solid foundation on which to continue your journey with Reason.

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Table of Contents (10 chapters)
Preface
Preface
Who this book is for
What this book covers
To get the most out of this book
Get in touch
Free Chapter
1
Introduction to ReasonML
Introduction to ReasonML
What is ReasonML?
Why Reason?
Exploring Reason
Summary
2
Setting Up a Development Environment
Setting Up a Development Environment
The Reason toolchain
Setting up a pure Reason project
Setting up a ReasonReact project
Summary
3
Creating ReasonReact Components
Creating ReasonReact Components
Component creation basics
Stateful components
Navigation menu
Client-side routing
Summary
4
BuckleScript, Belt, and Interoperability
BuckleScript, Belt, and Interoperability
Module scope
Data structures
Pipe operators
Using Belt
JavaScript interoperability
Binding to existing ReactJS components
Summary
5
Effective ML
Effective ML
Module signatures
Using module signatures
Phantom types
Polymorphic variants
Advanced type system features
Summary
6
CSS-in-JS (in Reason)
CSS-in-JS (in Reason)
What is CSS-in-JS?
Using styled-components
Using bs-css
Summary
7
JSON in Reason
JSON in Reason
Building views
Integrating with localStorage
Using bs-json
Using GraphQL
Summary
8
Unit Testing in Reason
Unit Testing in Reason
Testing with Jest
Summary
9
Other Books You May Enjoy
Other Books You May Enjoy
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Using bs-json

Now that we understand exactly how to convert JSON strings into typed Reason data structures, we notice that the process is a bit tedious. It's more lines of code than one would expect coming from a dynamic language such as JavaScript. Also, there is quite a bit of repetitive code. As an alternative, many in the Reason community have adopted bs-json as an "official" solution for encoding and decoding JSON.

Let's create a new module called DataBsJson.re and a new interface file, DataBsJson.rei. We'll copy the exact same interface as we had in DataPureReason.rei so that we know that, once we're done, we'll be able to replace all references to DataPureReason with DataBsJson and everything should work the same.

The exposed interface is as follows:

/* DataBsJson.rei */
[@bs.val] [@bs.scope "localStorage"] external getItem: string...
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