carl-calculator/script.js

let chartInstance = null;

document.querySelectorAll('[data-dollar]').forEach(function (input) {
  input.addEventListener('input', function () {
    var raw = this.value.replace(/[^0-9]/g, '');
    if (raw === '') {
      this.value = '';
      return;
    }
    this.value = parseInt(raw, 10).toLocaleString('en-US');
  });

  input.addEventListener('blur', function () {
    var raw = this.value.replace(/[^0-9]/g, '');
    if (raw === '') {
      this.value = '0';
    } else {
      this.value = parseInt(raw, 10).toLocaleString('en-US');
    }
  });
});

document.getElementById('calculator-form').addEventListener('submit', function (e) {
  e.preventDefault();
  const resultsInflation = runProjection(true);
  const resultsNoInflation = runProjection(false);
  renderTable(resultsInflation, 'results-table-inflation');
  renderTable(resultsNoInflation, 'results-table-noinflation');
  renderChart(resultsInflation);
  document.getElementById('results').classList.remove('hidden');
});

function getVal(id) {
  var el = document.getElementById(id);
  var raw = el.value.replace(/[^0-9.]/g, '');
  return parseFloat(raw) || 0;
}

function fmt(n) {
  return n.toLocaleString('en-US', { minimumFractionDigits: 0, maximumFractionDigits: 0 });
}

function runProjection(useInflation) {
  const years = 30;
  const inflationFactor = useInflation ? 1 + getVal('inflation') / 100 : 1;
  const growthFactor = 1 + getVal('ror') / 100;
  const taxRate = getVal('tax-rate') / 100;

  let pretax = getVal('pretax-value');
  let aftertax = getVal('aftertax-value');
  let roth = getVal('roth-value');
  let realEstate = getVal('realestate-value');

  let pretaxSpend = getVal('pretax-spending');
  let aftertaxSpend = getVal('aftertax-spending');
  let rothSpend = getVal('roth-spending');

  const rows = [];

  for (let y = 0; y <= years; y++) {
    const total = Math.round(pretax + aftertax + roth + realEstate);
    const prevTotal = rows.length > 0 ? rows[rows.length - 1].total : total;
    rows.push({
      year: y,
      pretax: Math.round(pretax),
      aftertax: Math.round(aftertax),
      roth: Math.round(roth),
      realEstate: Math.round(realEstate),
      total: total,
      yoyGrowth: Math.round(total - prevTotal),
      pretaxSpend: Math.round(pretaxSpend),
      aftertaxSpend: Math.round(aftertaxSpend),
      rothSpend: Math.round(rothSpend),
    });

    if (y === years) break;

    pretax = pretax * growthFactor;
    aftertax = aftertax * growthFactor;
    roth = roth * growthFactor;
    realEstate = realEstate * growthFactor;

    var cascadeSpend = 0;

    var grossPreTaxSpend = pretaxSpend / (1 - taxRate);
    if (grossPreTaxSpend > pretax) {
      cascadeSpend += pretaxSpend - pretax * (1 - taxRate);
      pretax = 0;
    } else {
      pretax -= grossPreTaxSpend;
      pretax = Math.max(0, pretax);
    }

    if (aftertaxSpend > aftertax) {
      cascadeSpend += aftertaxSpend - aftertax;
      aftertax = 0;
    } else {
      aftertax -= aftertaxSpend;
      aftertax = Math.max(0, aftertax);
    }

    if (rothSpend > roth) {
      cascadeSpend += rothSpend - roth;
      roth = 0;
    } else {
      roth -= rothSpend;
      roth = Math.max(0, roth);
    }

    if (cascadeSpend > 0) {
      var grossCascade = cascadeSpend / (1 - taxRate);
      if (aftertax > 0) {
        var aftertaxDraw = Math.min(cascadeSpend, aftertax);
        aftertax -= aftertaxDraw;
        aftertax = Math.max(0, aftertax);
        cascadeSpend -= aftertaxDraw;
      }
      if (cascadeSpend > 0 && pretax > 0) {
        var pretaxDraw = Math.min(cascadeSpend / (1 - taxRate), pretax);
        pretax -= pretaxDraw;
        pretax = Math.max(0, pretax);
        cascadeSpend -= pretaxDraw * (1 - taxRate);
      }
      if (cascadeSpend > 0 && roth > 0) {
        var rothDraw = Math.min(cascadeSpend, roth);
        roth -= rothDraw;
        roth = Math.max(0, roth);
      }
    }

    pretaxSpend *= inflationFactor;
    aftertaxSpend *= inflationFactor;
    rothSpend *= inflationFactor;
  }

  return rows;
}

function renderTable(rows, tableId) {
  const tbody = document.querySelector('#' + tableId + ' tbody');
  tbody.innerHTML = '';

  rows.forEach(function (r) {
    const growthColor = r.yoyGrowth >= 0 ? 'color:#16a34a' : 'color:#dc2626';
    const growthPrefix = r.yoyGrowth >= 0 ? '+$' : '-$';
    const growthStr = r.year === 0 ? '—' : '<span style="' + growthColor + '">' + growthPrefix + fmt(Math.abs(r.yoyGrowth)) + '</span>';
    const tr = document.createElement('tr');
    tr.innerHTML =
      '<td>' + r.year + '</td>' +
      '<td>$' + fmt(r.pretax) + '</td>' +
      '<td>$' + fmt(r.aftertax) + '</td>' +
      '<td>$' + fmt(r.roth) + '</td>' +
      '<td>$' + fmt(r.realEstate) + '</td>' +
      '<td>$' + fmt(r.total) + '</td>' +
      '<td>' + growthStr + '</td>' +
      '<td>$' + fmt(r.pretaxSpend) + '</td>' +
      '<td>$' + fmt(r.aftertaxSpend) + '</td>' +
      '<td>$' + fmt(r.rothSpend) + '</td>';
    tbody.appendChild(tr);
  });
}

function renderChart(rows) {
  const labels = rows.map(function (r) { return 'Year ' + r.year; });

  const datasets = [
    {
      label: 'Pre-tax',
      data: rows.map(function (r) { return r.pretax; }),
      borderColor: '#2563eb',
      backgroundColor: 'rgba(37, 99, 235, 0.08)',
      fill: true,
      tension: 0.3,
    },
    {
      label: 'After-tax',
      data: rows.map(function (r) { return r.aftertax; }),
      borderColor: '#16a34a',
      backgroundColor: 'rgba(22, 163, 74, 0.08)',
      fill: true,
      tension: 0.3,
    },
    {
      label: 'Roth',
      data: rows.map(function (r) { return r.roth; }),
      borderColor: '#dc2626',
      backgroundColor: 'rgba(220, 38, 38, 0.08)',
      fill: true,
      tension: 0.3,
    },
    {
      label: 'Real Estate',
      data: rows.map(function (r) { return r.realEstate; }),
      borderColor: '#f59e0b',
      backgroundColor: 'rgba(245, 158, 11, 0.08)',
      fill: true,
      tension: 0.3,
    },
    {
      label: 'Total Net Worth',
      data: rows.map(function (r) { return r.total; }),
      borderColor: '#7c3aed',
      backgroundColor: 'transparent',
      borderWidth: 2.5,
      tension: 0.3,
    },
  ];

  if (chartInstance) {
    chartInstance.destroy();
  }

  const ctx = document.getElementById('projection-chart').getContext('2d');
  chartInstance = new Chart(ctx, {
    type: 'line',
    data: { labels: labels, datasets: datasets },
    options: {
      responsive: true,
      maintainAspectRatio: false,
      interaction: {
        mode: 'index',
        intersect: false,
      },
      plugins: {
        tooltip: {
          callbacks: {
            label: function (context) {
              return context.dataset.label + ': $' + fmt(context.parsed.y);
            },
          },
        },
        legend: {
          position: 'bottom',
          labels: {
            usePointStyle: true,
            pointStyle: 'circle',
            padding: 16,
            font: { size: 12 },
          },
        },
      },
      scales: {
        x: {
          grid: { display: false },
          ticks: { maxTicksLimit: 11 },
        },
        y: {
          ticks: {
            callback: function (v) { return '$' + fmt(v); },
          },
        },
      },
    },
  });
}