Currying

Problem

Functions may have a high arity, which means that they can accept a lot of arguments. This is not optimal for at least two reasons:

1. Keeping a nice-looking indentation is hard if the list of parameters is really long
2. It is difficult for the programmer to remember the order of many positional parameters

Solution

We can use currying to reduce the arity of a function. The aim of this pattern is to transform a function with many parameters into multiple functions with only one parameter. Since JavaScript is an extremely flexible language, the only thing to do is to create a sort of "return chain" where each function returns another function (with only one parameter) until the number of parameters is exhausted.