demo D256

Fan chart in ESM

An actual line that opens into a forecast band, widening the further ahead it reaches

type: 'fan', x, y, forecast, lower, upper

This draws an actual line that opens into a forecast band, widening the further ahead it reaches. It shows a projection with its growing uncertainty, so a reader sees not just the estimate but how confident it is.

Building…

Loading a live grid…

This is the ES module version. The grid is imported straight from a CDN as a module, the same configuration as the vanilla tab without a global script tag, so it drops into any bundler or a bare module script.

The configuration

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@toclocoinc/lattice-grid@1.71.0/lattice-grid.min.css">

<div id="grid" style="height: 320px"></div>
<div id="chart" style="height: 340px"></div>

<script type="module">
  import { createChart } from '@toclocoinc/lattice-grid/modules/charts';
  import '@toclocoinc/lattice-grid/modules/chart-fan';  // opt in to the fan type

  const grid = createGrid(document.getElementById('grid'), {
    rowKey: 'id',
    columns: [
      { field: 'month', title: 'Month' },
      { field: 'actual', title: 'Actual', type: 'number' },
      { field: 'forecast', title: 'Forecast', type: 'number' },
      { field: 'lower', title: 'Lower', type: 'number' },
      { field: 'upper', title: 'Upper', type: 'number' },
    ],
    rows,  // actuals then a forecast band: month, actual, forecast, lower, upper
  });

  // A solid line for the actuals, then a band from lower to upper that widens
  // the further ahead the forecast reaches.
  createChart({
    grid,
    container: document.getElementById('chart'),
    type: 'fan',
    x: 'month',
    y: 'actual',
    forecast: 'forecast',
    lower: 'lower',
    upper: 'upper',
    title: 'Actuals, then a forecast with its range',
  });
</script>