currying.md

Currying in JavaScript is a functional programming technique that involves converting a function with multiple arguments into a series of nested functions. This leads to the generation of a new function that expects each following argument one after the other.

In simpler terms, rather than a function receiving all its arguments simultaneously, it initially takes the first one and produces a new function. This new function, in turn, takes the second argument and yields another function, continuing this pattern until all arguments are satisfied.

Curried functions are formed by creating a sequence of closures, wherein each closure defines and immediately returns its inner function.

// normal function with arity of 3
function sum(a, b, c) {
    return a + b + c;
}
sum(1,2,3); // 6


// curried function
function sum(a) {
    return (b) => {
        return (c) => {
            return a + b + c
        }
    }
}
console.log(sum(1)(2)(3)) // 6

Pros:

• It can make your code more readable and expressive.
• It allows you to create specialized functions from more general ones.
• It can be useful in asynchronous code because it allows you to delay a computation until all the arguments are available.

Cons:

• It can make your code harder to understand if you're not familiar with the concept.
• It can lead to a performance overhead because of the creation of many intermediate functions.

Kyle Simpson, author of the "You Don't Know JS" book series, says: "Currying is a way of thinking about functions that allows us to use the functional nature of JavaScript to our advantage."