day-01.js

// https://adventofcode.com/2020/day/1

const inputText = `
  1782
  1344
  1974
  1874
  1800
  1973
  1416
  1952
  1982
  1506
  1642
  1514
  1978
  1895
  1747
  1564
  1398
  1683
  1886
  1492
  1629
  1433
  295
  1793
  1740
  1852
  1697
  1471
  1361
  1751
  1426
  2004
  1763
  1663
  1742
  1666
  1733
  1880
  1600
  1723
  1478
  1912
  1820
  1615
  1875
  1547
  1554
  752
  1905
  1368
  954
  1425
  1391
  691
  1835
  744
  1850
  1713
  1995
  1926
  1817
  1774
  1986
  2010
  1427
  1609
  1927
  1362
  1420
  1722
  1590
  1925
  1617
  1434
  1826
  1636
  1687
  1946
  704
  1797
  1517
  1801
  1865
  1963
  1828
  1829
  1955
  1832
  1987
  1585
  1646
  1575
  1351
  1345
  1729
  1933
  1918
  1902
  1490
  1627
  1370
  1650
  1340
  1539
  1588
  1715
  1573
  1384
  1403
  1673
  1750
  1578
  1831
  1849
  1719
  1359
  2008
  1837
  1958
  480
  1388
  1770
  1999
  1066
  1730
  1541
  1802
  1962
  1891
  1816
  1505
  1665
  1551
  1954
  1378
  1998
  1612
  1544
  1953
  1502
  1888
  1655
  1614
  1903
  1675
  1498
  1653
  1769
  1863
  1607
  1945
  1651
  1558
  1777
  1460
  1711
  1677
  1988
  1441
  1821
  1867
  1656
  1731
  1885
  1482
  1439
  1990
  1809
  1794
  1951
  1858
  1969
  509
  1486
  1971
  1557
  1896
  1884
  1834
  1814
  1216
  1997
  1966
  1808
  1754
  1804
  1684
  2001
  1699
  1781
  1429
  1322
  1603
  1596
  1823
  1700
  1552
  1352
  1621
  1669
`;

const testInputText = `
  1721
  979
  366
  299
  675
  1456
`;

function parseInput(inputText) {
  return inputText
    .trim()
    .split('\n')
    .map(n=> parseInt(n));
}

function resolveStar1(input) {
  let result = 0;
  input.forEach(number1 => {
    input.forEach(number2 => {
      if (number1 + number2 === 2020) {
        console.log('hey')
        result = number1 * number2;
      }
    })
  })

  return result;
}

function resolveStar2(input) {
  let result = 0;
  input.forEach(number1 => {
    input.forEach(number2 => {
      input.forEach(number3 => {
        if (number1 + number2 + number3 === 2020) {
          result = number1 * number2 * number3;  
        }
      })
    })
  })

  return result;
}

const input = parseInput(inputText);

const resultOne = resolveStar1(input);
console.log(`For first star, two entries multiplied = ${resultOne}`);

const resultTwo = resolveStar2(input);
console.log(`For second star, three entries multiplied = ${resultTwo}`);