Not So Easy Functional Programming in JavaScript

Introduction

JavaScript allows for operating on arrays in a functional way, e.g. using filter or map functions. As an argument for these functions, we can pass lambda expressions or function references. Is there a difference between them? The answer is yes.

What's the Problem?

In our project, we are building a mapping using the String.fromCharCode function. To simplify the usage of this function, my code looked similar to: