ReasonML Quick Start Guide

Array

Reason arrays compile to regular JavaScript arrays. Reason arrays are as follows:

• Homogeneous (all elements must be of the same type)
• Mutable
• Fast at random access and updates

They look like this:

let array = [|"first", "second", "third"|];

Accessing and updating elements of an array are the same as in JavaScript:

array[0] = "updated";

In JavaScript, we map over the array, as follows:

/* JavaScript */array.map(e => e + "-mapped")

To do the same in Reason, we have a few different options.