--description--

Given an amount of money you have, and an array of items you want to buy, determine how many of them you can afford.

• The given amount will be in the format ["Amount", "Currency Code"]. For example: ["150.00", "USD"] or ["6000", "JPY"].
• Each array item you want to purchase will be in the same format.

Use the following exchange rates to convert values:

• If you can afford all the items in the list, return "Buy them all!".
• Otherwise, return "Buy the first X items.", where X is the number of items you can afford when purchased in the order given.

--hints--

buyItems(["150.00", "USD"], [["50.00", "USD"], ["75.00", "USD"], ["30.00", "USD"]]) should return "Buy the first 2 items.".

assert.equal(buyItems(["150.00", "USD"], [["50.00", "USD"], ["75.00", "USD"], ["30.00", "USD"]]), "Buy the first 2 items.");

buyItems(["200.00", "EUR"], [["50.00", "USD"], ["50.00", "USD"]]) should return "Buy them all!".

assert.equal(buyItems(["200.00", "EUR"], [["50.00", "USD"], ["50.00", "USD"]]), "Buy them all!");

buyItems(["100.00", "CAD"], [["20.00", "USD"], ["15.00", "EUR"], ["10.00", "GBP"], ["6000", "JPY"], ["5.00", "CAD"], ["10.00", "USD"]]) should return "Buy the first 3 items.".

assert.equal(buyItems(["100.00", "CAD"], [["20.00", "USD"], ["15.00", "EUR"], ["10.00", "GBP"], ["6000", "JPY"], ["5.00", "CAD"], ["10.00", "USD"]]), "Buy the first 3 items.");

buyItems(["5000", "JPY"], [["3.00", "USD"], ["1000", "JPY"], ["5.00", "CAD"], ["2.00", "EUR"], ["4.00", "USD"], ["2000", "JPY"]]) should return "Buy them all!".

assert.equal(buyItems(["5000", "JPY"], [["3.00", "USD"], ["1000", "JPY"], ["5.00", "CAD"], ["2.00", "EUR"], ["4.00", "USD"], ["2000", "JPY"]]), "Buy them all!");

buyItems(["200.00", "USD"], [["50.00", "USD"], ["40.00", "EUR"], ["30.00", "GBP"], ["5000", "JPY"], ["25.00", "CAD"], ["20.00", "USD"]]) should return "Buy the first 5 items.".

assert.equal(buyItems(["200.00", "USD"], [["50.00", "USD"], ["40.00", "EUR"], ["30.00", "GBP"], ["5000", "JPY"], ["25.00", "CAD"], ["20.00", "USD"]]), "Buy the first 5 items.");

--seed--

--seed-contents--

function buyItems(funds, items) {

  return funds;
}

--solutions--

function buyItems(funds, items) {
  const rates = {
    USD: 1.00,
    EUR: 1.10,
    GBP: 1.25,
    JPY: 0.0070,
    CAD: 0.75
  };

  const [amount, currency] = funds;
  let money = parseFloat(amount) * rates[currency];

  for (let i = 0; i < items.length; i++) {
    const [itemAmount, itemCurrency] = items[i];
    const itemCostUSD = parseFloat(itemAmount) * rates[itemCurrency];

    if (itemCostUSD > money) {
      return `Buy the first ${i} items.`;
    }

    money -= itemCostUSD;
  }

  return "Buy them all!";
}