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

# What is a Function?

The concept of functions is one of the most powerful tools in modern programming.

A function, or **method**, can be thought of as an entity that contains a set of operations. Whenever a function is *called* the operations are executed in order to return a value. In this sense, functions themselves can be thought of as predefined expressions.

A big syntactical advantage of functions is that they erase the need to write the same code over and over again. A function acts as a block which performs an operation we need to reuse over and over again.


# Reason's Approach
Reason is a **functional programming language** which means that it relies heavily on functions. Functions are responsible for the flow of information in a Reason application.

## Examples 

We've already seen several instances of the built-in functions of Reason. For arrays, we have the `Arrays.make()` function to create a dynamic array. The `String.contains()` method was also an example of a function. Both of these functions performed a predefined task. We did not have to write the logic behind them again and again in our program. That is the beauty of functions.

Though it may feel a bit weird that we are discussing them so late in the course, do not worry. The concepts which we've studied up to now will only make functions easier to understand. 

In the following lessons, we'll understand the true potential of functions in Reason.

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Let's get started by creating our first function!



In this section, we'll learn why the use of functions is essential in ReasonML.

A Brief Introduction

Data Types

Identifiers

Data Structures

Conditional Expressions

Functions

Loops

Variants

Objects

Introduction

What is a Function?