4-tax.js

/*
  SALES TAX
  =========
  A business requires a program that calculates how much sales tax to charge
  Sales tax is 20% of the price of the product
*/

function calculateSalesTax(sales) {
  var tax = .2;
  var salesTax = sales * tax;
  var twoDecimals = salesTax.toFixed(2); // to add 2 decimal places
  var twoDecimalsNum = parseFloat(twoDecimals); // converts text to number
  return sales + twoDecimalsNum;

  // var salesaddedTax = sales * 1.2;
  // var twoDecimals = salesaddedTax.toFixed(2);
  // return twoDecimals;
}
console.log(calculateSalesTax(17.5));
console.log(calculateSalesTax(34));

/*
  CURRENCY FORMATTING
  ===================
  The business has informed you that prices must have 2 decimal places
  They must also start with the currency symbol
  Write a function that transforms numbers into the format £0.00

  Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
*/

function formatCurrency(sales) {
  function calculateSalesTax(sales) {
    var tax = .2;
    var salesTax = sales * tax;
    var twoDecimals = salesTax.toFixed(2); // to add 2 decimal places
    var twoDecimalsNum = parseFloat(twoDecimals); // converts text to number
    return sales + twoDecimalsNum;
  }
  var number = calculateSalesTax(sales);
  console.log(new Intl.NumberFormat('en-GB', {
    style: 'currency',
    currency: 'GBP'
  })
  .format(number)
  );
}

// var number = calculateSalesTax(34);
// console.log(new Intl.NumberFormat('en-GB', {
//     style: 'currency',
//     currency: 'GBP'
//   })
//   .format(number)
// );


/* ======= TESTS - DO NOT MODIFY ===== 
There are some Tests in this file that will help you work out if your code is working.

To run these tests type `node 4-tax.js` into your terminal
*/

function test(test_name, expr) {
  let status;
  if (expr) {
    status = "PASSED";
  } else {
    status = "FAILED";
  }

  console.log(`${test_name}: ${status}`);
}

test("calculateSalesTax function - case 1 works", calculateSalesTax(15) === 18);
test(
  "calculateSalesTax function - case 2 works",
  calculateSalesTax(17.5) === 21
);
test(
  "calculateSalesTax function - case 3 works",
  calculateSalesTax(34) === 40.8
);

test("formatCurrency function - case 1 works", formatCurrency(15) === "£18.00");
test(
  "formatCurrency function - case 2 works",
  formatCurrency(17.5) === "£21.00"
);
test("formatCurrency function - case 3 works", formatCurrency(34) === "£40.80");