Explore ReasonML's growing popularity and its strong-typed syntax for JavaScript. Learn about creating data objects, functions, and data structures through interactive quizzes and exercises.

ReasonML has been skyrocketing in popularity lately, and for good... reason. Very recently developed by Facebook, it provides users a strong-typed, clean, and efficient syntax for JavaScript, which makes it great for web development. 

This course will get you up to speed programming in Reason. You'll start by learning how to create simple data objects and build up to more powerful tools such as functions and data structures. Along the way, interactive quizzes and exercises will help you gain a stronger grasp of the language.

Anyone looking to put themselves on the cutting-edge of web development would be well served to have a look at this course.

Functional Programming with ReasonML

A `while` loop is slightly different from the previously visited `for` loop. Instead of relying on a defined range, it runs as long as a **boolean expression** holds **true**. 

# The Structure
The template for a `while` loop is fairly simple:

while(boolean expression) {
  set of operations
};

The logic of this structure lies in the `boolean expression`. At some point, the value of the expression has to change from *true* to *false*. From this, we can make the deduction that the expression will contain a variable whose value updates in the body of the loop until it turns the `boolean expression` into a *false* one.

We can think of this variable or value as the iterator in a `for` loop.

> **Warning**: If the boolean expression of the `while` always holds *true*, the loop will keep running forever, resulting in a potential!

In order to change the value of the `boolean expression`, a part of it must be **mutable**. Hence, a good practice is to stick to mutable entities when dealing with `while` loops.

# The Syntax
Let's write a simple `while` loop which prints integers from `0` to `10`:

Let's take a look at some of the key features of the while loop.

A Brief Introduction

Data Types

Identifiers

Data Structures

Conditional Expressions

Functions

Loops

Variants

Objects

While Loops