CODE EXAMPLE FOR JAVASCRIPT

declerative and imperative program combine

// "hidden" in a utils/helper/whatever module, or library-like
function transformEachElement<A, B>(
  elements: A,
  action: (element: A) => B
): B[] {
  const result = []
  for (let i = 0; i < elements.length: i++) {
    result.push(action(elements[i]))
  }
  return result
}

// What do we want? Double each number of a given list
const res = transformEachElement([1, 2, 3], n => n * 2)