javascriptfunctional-programmingterminologydefinitioncurrying

What is 'Currying'?

I've seen references to curried functions in several articles and blogs but I can't find a good explanation (or at least one that makes sense!)

Solution

  • Currying is when you break down a function that takes multiple arguments into a series of functions that each take only one argument. Here's an example in JavaScript:

    function add (a, b) {
    return a + b;
}

add(3, 4); // returns 7

    This is a function that takes two arguments, a and b, and returns their sum. We will now curry this function:

    function add (a) {
    return function (b) {
        return a + b;
    }
}

    This is a function that takes one argument, a, and returns a function that takes another argument, b, and that function returns their sum.

    add(3)(4); // returns 7

var add3 = add(3); // returns a function

add3(4); // returns 7