Confidence intervals, charted

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@toclocoinc/lattice-grid@1.13.0/lattice-grid.min.css">
<script src="https://cdn.jsdelivr.net/npm/@toclocoinc/lattice-grid@1.13.0/lattice-grid.min.js"></script>

<div id="chart" style="height:250px"></div>
<div id="tiles" style="display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:14px 0"></div>
<div id="grid" style="height:340px"></div>

<script type="module">
  import { createGrid, createStat } from 'https://cdn.jsdelivr.net/npm/@toclocoinc/lattice-grid@1.13.0';
  import { createChart } from 'https://cdn.jsdelivr.net/npm/@toclocoinc/lattice-grid@1.13.0/modules/charts';

  const grid = createGrid(document.getElementById('grid'), {
    rowKey: 'id',
    toolPanel: { side: 'left', panels: ['filters', 'columns', 'statistics'] },
    columns: [
      { field: 'supplier', title: 'Supplier', filter: { type: 'set' } },
      { field: 'days', title: 'Lead time', type: 'number', format: { suffix: ' d', maximumFractionDigits: 1 }, total: 'avg' },
    ],
    rows,  // e.g. [{ id: 'O0', supplier: 'Kestrel', days: 3.1 }, …]
  });

  // interval() is the range the mean is pinned to, computed over the filtered
  // rows. The tile shows it under the value; ask for a proportion with
  // { kind: 'proportion' } and a rule for what counts as a success.
  const tile = () => document.getElementById('tiles').appendChild(document.createElement('div'));
  createStat({ grid, container: tile(), title: 'Mean lead time', of: 'days', fn: 'avg',
    interval: (value, grid) => grid.statistics.interval('days'), footer: '95% confidence interval' });

  // error: true draws each mean's 95% interval as a whisker, computed from the
  // readings behind the bar. The chart reads the same grid as the tile, so the
  // bars and the whiskers follow the filters.
  createChart({ grid, container: '#chart', type: 'bar', x: 'supplier', y: { col: 'days', fn: 'avg' },
    error: true, title: 'Mean lead time by supplier, with 95% confidence interval' });
</script>