write a program that will be used in a vending machine to return change

change.js

/**
 * Problem Statement:
 *
 * A vending machine has the following denominations: 1c, 5c, 10c, 25c, 50c, and $1.
 * Your task is to write a program that will be used in a vending machine to return change.
 * Assume that the vending machine will always want to return the least number of coins or notes.
 * Devise a function getChange (M, P)
 * where M is how much money was inserted into the machine and P the price of the item selected,
 * that returns an array of integers representing the number of each denomination to return.
 *
 * Example:
 * getChange (5, 0.99) // should return [1,0,0,0,0,4]
 * getChange (3.14, 1.99) // should return [0,1,1,0,0,1]
 * getChange (3, 0.01) // should return [4,0,2,1,1,2]
 * getChange(4, 3.14) // should return [1,0,1,1,1,0]
 * getChange (0.45, 0.34) // should return [1,0,1,0,0,0]
 */

/**
 * Calculates the change given the amount of money and the price of the item.
 * @param {number} m - the amount of money given
 * @param {number} p - the price of the item
 * @returns {number[]} - the change given in the form of an array of numbers
 *
 * @author: msamgan
 * @date: 8th June, 2022
 * @version: 1.0
 */
const getChange = async (m, p) => {
  console.log(`m: ${m},  p: ${p}`);

  if (p > m) {
    console.log("ERROR: Not enough money");
    return;
  }

  let denominations = [1, 5, 10, 25, 50, 100];
  let change = [0, 0, 0, 0, 0, 0];

  let changeAmount = Number(m - p).toFixed(2);

  let changeAmountFloor = Math.floor(changeAmount);
  let decimalPart = Number(changeAmount.toString().split(".")[1]);

  for (let i = 1; i <= denominations.length; i++) {
    let changeIndex = denominations.length - i;

    if (i === 1) {
      change[changeIndex] = changeAmountFloor;
      continue;
    }

    let dividend = decimalPart / denominations[changeIndex];

    if (dividend <= 0) {
      continue;
    }

    change[changeIndex] = Math.floor(dividend);

    decimalPart = Number(
      (decimalPart - Math.floor(dividend) * denominations[changeIndex]).toFixed(
        2
      )
    );
  }

  return change;
};

// sample inputs
// 5, 0.99
// 3.14, 1.99
// 3, 0.01
// 4, 3.14
// 0.45, 0.34
getChange(3.14, 1.99).then((response) => {
  console.log(response);
});