A simple example of currying in JS

// This is a 'curried' function. If it receives less params than it expects, it returns a function which expects the rest of the params. function add(a, b) { // if 2nd param wasn't passed, return a function that holds the 1st param via closure, but expects another param. if (typeof b === "undefined") { return function(c) { a + c; } }

// if 2 params are passed return the result return a + b; }

add(2,2); // 4

// we are now using the curried function add(1)(2); // 3

// and we can do this... var add2 = add(2); add2(3); // 5

// some more reading here: // https://javascriptweblog.wordpress.com/2010/04/05/curry-cooking-up-tastier-functions/