chartjs/Chart.js · error · Error

No dataset found at index ${datasetIndex}

Error message

No dataset found at index ${datasetIndex}

What it means

Chart.setActiveElements maps each {datasetIndex, index} to a meta via getDatasetMeta(datasetIndex). getDatasetMeta returns the dataset metadata only if the index is within the currently built _metasets; otherwise it returns undefined. When the caller passes a datasetIndex that was never built (out of range or before the first update), meta is falsy and this error is thrown. This is a public API for programmatically setting hovered/active points.

Source

Thrown at src/core/core.controller.js:1101

  /**
	 * Get active (hovered) elements
	 * @returns array
	 */
  getActiveElements() {
    return this._active || [];
  }

  /**
	 * Set active (hovered) elements
	 * @param {array} activeElements New active data points
	 */
  setActiveElements(activeElements) {
    const lastActive = this._active || [];
    const active = activeElements.map(({datasetIndex, index}) => {
      const meta = this.getDatasetMeta(datasetIndex);
      if (!meta) {
        throw new Error('No dataset found at index ' + datasetIndex);
      }

      return {
        datasetIndex,
        element: meta.data[index],
        index,
      };
    });
    const changed = !_elementsEqual(active, lastActive);

    if (changed) {
      this._active = active;
      // Make sure we don't use the previous mouse event to override the active elements in update.
      this._lastEvent = null;
      this._updateHoverStyles(active, lastActive);
    }
  }

View on GitHub (pinned to cb02e1d207)

Solutions

1. Ensure the chart has fully rendered (await next frame / chart.update()) before calling setActiveElements.
2. Clamp datasetIndex against chart.data.datasets.length before calling: if (i >= 0 && i < chart.data.datasets.length).
3. Re-derive the active elements from the current datasets after any data change that removes datasets.
4. Guard with chart.getDatasetMeta(i) returning truthy before including the entry.

Example fix

// before
chart.setActiveElements([{ datasetIndex: 3, index: 2 }]); // chart has only 2 datasets -> throws

// after
const safe = [{ datasetIndex: 3, index: 2 }].filter(
  ({ datasetIndex }) => datasetIndex >= 0 && datasetIndex < chart.data.datasets.length
);
chart.setActiveElements(safe);

// Clamp/filter active elements to valid dataset indices before calling setActiveElements.
function safeSetActiveElements(chart, activeElements) {
  const n = chart.data.datasets.length;
  const safe = activeElements.filter(
    ({ datasetIndex, index }) =>
      Number.isInteger(datasetIndex) && datasetIndex >= 0 && datasetIndex < n &&
      Number.isInteger(index) && index >= 0
  );
  if (safe.length) chart.setActiveElements(safe);
  else chart.setActiveElements([]);
}

// Narrow to well-formed active-element entries.
function isValidActiveElement(e, datasetCount) {
  return (
    e && typeof e.datasetIndex === 'number' && typeof e.index === 'number' &&
    e.datasetIndex >= 0 && e.datasetIndex < datasetCount && e.index >= 0
  );
}

When it happens

Trigger: Calling chart.setActiveElements([{datasetIndex: 5, index: 0}]) when the chart has fewer datasets; calling it before chart.update()/render has built metasets (e.g. synchronously after `new Chart` before the first render frame); passing an index derived from stale data after datasets were removed.

Common situations: Setting active elements in a unit test immediately after construction; syncing selection state from a parent component whose dataset count differs from the chart; restoring saved active state after replacing data with a shorter array.

Related errors

• Cannot find a dataset at index ${datasetIndex}
• Cannot determine type of '${id}' axis. Please provide 'axis'

AI-assisted analysis of chartjs/Chart.js@cb02e1d207 (2026-08-12). Data as JSON: /api/errors/349da5e806899f56. Report an issue: GitHub.