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Porting my site to Reason

cvr profile image Cristian Velasquez Ramos Originally published at cvr.im ・1 min read

I've heard of ReasonML for a while now.

It's a language that always intrigued me since I'm a fan of FP patterns.
Well, I finally got around to really diving deep into it (aside from todos 😅).

Reason is not too different from JS/TS so the port was mainly about stripping away all the TypeScript types and letting the compiler infer the rest.

I've got to say, my favourite thing about Reason is the Rescript compiler. The inference it provides is great! It makes it so you only have to provide types at the very bottom level.

What do I mean?

Take for example this code:

module Component = {
  let make = (~name) => <div> React.string(name) </div>

// using the component
<Component name="Bob"/>
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As you can see, I haven't declared a single type. The prop name is inferred to be a string because it's used with React.string!

The type of React.string is something like this:

module React {
  let string: string => string = //..
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A major pain point I have though is that modeling data can be a bit of a hassle. There is no extending base types within Reason/Rescript (there is in ocaml), so something as simple as this requires copy pasting:

interface Person {
  name: sting;

interface Employee extends Person {
  company: string;
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The Reason equivalent is:

type person = {
  name: string

type employee = {
  name: string,
  company: string
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Overall, I really enjoy using Reason/Rescript. Just the inference itself is enough for me to reach for it whenever I can!


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