Discussion on: Currying in JS 🤠

[Amin]

Hi there and thanks for your article!

In my opinion, this article deserves a little bit more explanations, especially the usefulness of using curried functions.

If I start from your example.

const isDivisible = divider => number => !(number % divider);

console.log(isDivisible(2)(40)); // true
console.log(isDivisible(2)(33)); // false
console.log(isDivisible(3)(40)); // false
console.log(isDivisible(3)(33)); // true

Even though you have successfully curried your function, we can see that the 2 & 3 parameters could have been reused. Now if I take this example.

const isDivisible = divider => number => !(number % divider);

console.log(isDivisible(2)(40)); // true
console.log(isDivisible(2)(33)); // false
console.log(isDivisible(2)(29)); // false
console.log(isDivisible(2)(26)); // true

We can see that I'm repeating the 2 a lot. What is great about curried functions is that they can be used to compose higher order functions (a higher order function is a function that either takes a function as parameter or returns a new one), and so helping us reuse some parameters that are commons accross function calls.

const isDivisible = divider => number => !(number % divider);
const isDivisibleByTwo = isDivisible(2);

console.log(isDivisibleByTwo(40)); // true
console.log(isDivisibleByTwo(33)); // false
console.log(isDivisibleByTwo(26)); // true
console.log(isDivisibleByTwo(39)); // false

And this is, in my opinion, what makes currying so powerful. Composing functions helps you decrease the needs for repeating common parts of your application.

[Luke Bayliss]

This is what I was expecting to read!

[Marcos Henrique]

Thanks for the explanation,I tried to introduce the characteristic of flexibility, although this approach that you said was the most common as to the power of currying.