CURRYING.md

Currying

Currying is the technique of translating the evaluation of a function that takes N arguments into evaluating a sequence of N functions, each with a single argument.

This process is done by calling the function with one parameter, and return a new function with the parameter already bound inside a closure.

For example, let’s say we have an add function that takes two parameters a and b:

// The native function definition would be to have a and b as parameters:
add(3, 5)

// After currying the function, we can then apply it like so:
curryAdd(3)(5)

This is an interesting technique allowing to partially call a function, leaving the rest of the call for later.

For instance, with our previous curryAdd function:

var add3 = curryAdd(3);
var add10 = curryAdd(10);

// Then we can call
add3(5) // => 8
add10(5) // => 15

Lodash, Wu and Ramda are 3 of the many libraries that provide currying.