Kyrylo Yakymenko

Reason + TypeScript with genType

Incremental adoption in existing codebases

Backend: C# and F#

3 steps

• Step 0: Existing TypeScript codebase
• Step 1: Use a Reason function in JavaScript
• Step 2: Use a Reason function in TypeScript (genType)
• Step 3: Use a ReasonReact component in TypeScript

Step 0

Existing TypeScript codebase

Step 1

Call a function written in Reason from JavaScript

Step 2

Pull in genType

Retain type safety across languages

Step 3

Use a React component written in Reason in a TypeScript component

Starting from the "Leaves"

Other approaches

Adding ReasonML to a Vue application

"Edges" of the system (e.g. API calls)

Good use cases

• Domain modelling (ADTs)
• Pattern matching
• State machines

What to avoid

Questions?

GitHub, Twitter: Yakimych