Rediscovering JavaScript

Chapter 3

Here are the solutions to the ​Exercises​, for the Chapter 3, ​Working with Function Arguments​ chapter.

Exercise 1

'use strict';

const amountAfterTaxes = function(amount, ...taxes) {
  const computeTaxForAmount = function(tax) {
    return amount * tax / 100.0;
  };

  const totalValues = function(total, value) {
    return total + value;
  };

  return taxes.map(computeTaxForAmount)
    .reduce(totalValues, amount).toFixed(2);

  //or, using arrow functions:
  //return taxes.map(tax => amount * tax / 100.0)
  //  .reduce((total, value) => total + value, amount)
  //  .toFixed(2);
};

const amount = 25.12;
const fedTax = 10;
const stateTax = 2;
const localTax = 0.5;

console.log(amountAfterTaxes(amount)); ...