combined.js

const companies = [
    {name: "Company One", category: "Finance", start: 1981, end: 2003},
    {name: "Company Two", category: "Retail", start: 1992, end: 2008},
    {name: "Company Three", category: "Auto", start: 1999, end: 2007},
    {name: "Company Four", category: "Retail", start: 1989, end: 2010},
    {name: "Company Five", category: "Technology", start: 2009, end: 2014},
    {name: "Company Six", category: "Finance", start: 1987, end: 2010},
    {name: "Company Seven", category: "Auto", start: 1986, end: 1996},
    {name: "Company Eight", category: "Technology", start: 2011, end: 2016},
    {name: "Company Nine", category: "Retail", start: 1981, end: 1989}
  ];
  
  const ages = [33, 12, 20, 16, 5, 54, 21, 44, 61, 13, 15, 45, 25, 64, 32];

  
  //combined map, sort, filter, reduce
  const combined = companies.map(function(company) {
    return {
      name: company.name,
      category: company.category,
      start: company.start,
      end: company.end,
      age: ages.filter(function(age) {
        return age >= company.start && age <= company.end;
      })
    };
  }).sort(function(a, b) {
    return a.name.localeCompare(b.name);
  }).filter(function(company) {
    return company.age.length > 0;
  }).reduce(function(a, b) {
    return a + b.age.length;
  }, 0);

//   console.log(combined);

const combinedAges = ages
.map(age => age * 2)
.filter(age => age > 30)
.sort((a, b) => a - b)
.reduce((a, b) => a + b, 0);


console.log(combinedAges);