why do we currying functions in javascript code example

Example 1: currying in javascript

//No currying
function volume(w, h, l) {
  return w * h * l;
}

volume(4, 6, 3); // 72

//Currying
function volume(w) {
  return function(h) {
    return function(l) {
      return w * h* l;
    }
  }
}

volume(4)(6)(3); // 72

Example 2: what is a curried function

Curried Function
// Non-curried
function add(a, b, c) {
  return a + b + c
}

add(1, 2, 3)
//-> 6

// Curried
function addd(a) {
  return function (b) {
    return function (c) {
      return a + b + c
    }
  }
}

addd(1)(2)(3)
//-> 6