Chart.js module for charting boxplots and violin charts

Usage no npm install needed!

<script type="module">
  import sgratzlChartjsChartBoxplot from 'https://cdn.skypack.dev/@sgratzl/chartjs-chart-boxplot';


Chart.js Box and Violin Plot

License: MIT NPM Package Github Actions

Chart.js module for charting box and violin plots. This is a maintained fork of @datavisyn/chartjs-chart-box-and-violin-plot, which I originally developed during my time at datavisyn.

Box Plot Violin Plot

Related Plugins

Check out also my other chart.js plugins:


npm install --save chart.js @sgratzl/chartjs-chart-boxplot


see Samples on Github

and Open in CodePen


four new types: boxplot and violin.


The config can be done on a per dataset .data.datasets[0].minStats or for all datasets under the controllers name. e.g., .options.boxplot.datasets.minStats.

see https://github.com/sgratzl/chartjs-chart-boxplot/blog/dev/src/data.ts#L100-L147

Data structure

Both types support that the data is given as an array of numbers number[]. The statistics will be automatically computed. In addition, specific summary data structures are supported:

see https://github.com/sgratzl/chartjs-chart-boxplot/blog/dev/src/data.ts#L24-L49


In order to simplify the customization of the tooltips the tooltip item given to the tooltip callbacks was improved. The default toString() behavior should be fine in most cases. The tooltip item has the following structure:

interface ITooltipItem {
  label: string; // original
  value: {
    raw: IBoxPlotItem | IViolinItem;
     * in case an outlier is hovered this will contains its index
     * @default -1
    hoveredOutlierRadius: number;
     * toString function with a proper default implementation, which is used implicitly
    toString(): string;

    min: string;
    median: string;
    max: string;
    items?: string[];

    //... the formatted version of different attributes IBoxPlotItem or ViolinItem

ESM and Tree Shaking

The ESM build of the library supports tree shaking thus having no side effects. As a consequence the chart.js library won't be automatically manipulated nor new controllers automatically registered. One has to manually import and register them.

Variant A:

import { Chart, LinearScale, CategoryScale } from 'chart.js';
import { BoxPlotController, BoxAndWiskers } from '@sgratzl/chartjs-chart-boxplot';

// register controller in chart.js and ensure the defaults are set
Chart.register(BoxPlotController, BoxAndWiskers, LinearScale, CategoryScale);

new Chart(ctx, {
  type: 'boxplot',
  data: [...],

Variant B:

import { BoxPlotChart } from '@sgratzl/chartjs-chart-boxplot';

new BoxPlotChart(ctx, {
  data: [...],

Development Environment

npm i -g yarn
yarn install
yarn sdks vscode

Common commands

yarn compile
yarn test
yarn lint
yarn fix
yarn build
yarn docs


Original credits belong to @datavisyn.