test-react-chartjs-2

react-chartjs-2

React wrapper for Chart.js

Getting started

Install library with peer dependencies

npm install --save react-chartjs-2 chart.js

# or

yarn add react-chartjs-2 chart.js

We recommend using chart.js ^3.0.0

Usage

import { Doughnut } from 'react-chartjs-2';

<Doughnut data={...} />

Examples

Live: reactchartjs.github.io/react-chartjs-2

See these examples for more information

Configure

Chart props

  id?: string;
  className?: string;
  height?: number;
  width?: number;
  redraw?: boolean;
  type: Chart.ChartType
  data: Chart.ChartData | (canvas: HTMLCanvasElement | null) => Chart.ChartData;
  options?: Chart.ChartOptions;
  plugins?: Chart.PluginServiceRegistrationOptions[];
  getDatasetAtEvent?: (dataset: Array<{}>, event: React.MouseEvent<HTMLCanvasElement>) => void;
  getElementAtEvent?: (element: [{}], event: React.MouseEvent<HTMLCanvasElement>) => void;
  getElementsAtEvent?: (elements: Array<{}>, event: React.MouseEvent<HTMLCanvasElement>) => void;

id

Type string Default: undefined

ID attribute applied to the rendered canvas

className

Type string Default: undefined

class attribute applied to the rendered canvas

height

Type: number Default: 150

Height attribute applied to the rendered canvas

width

Type: number Default: 300

Width attribute applied to the rendered canvas

redraw

Type: boolean Default: false

If true, will tear down and redraw chart on all updates

type

Type: 'line' | 'bar' | 'horizontalBar' | 'radar' | 'doughnut' | 'polarArea' | 'bubble' | 'pie' | 'scatter'

Chart.js chart type (required only on ChartComponent)

data (required)

Type: Chart.ChartData | (canvas: HTMLCanvasElement | null) => Chart.ChartData

The data object that is passed into the Chart.js chart (more info).

This can also be a function, that receives a canvas element and returns the data object.

const data = canvas => {
    const ctx = canvas.getContext('2d');
    const g = ctx.createLinearGradient(...);

    return {
        datasets: [{
            backgroundColor: g,
            // ...the rest
        }],
    };
}

options

Type: Chart.ChartOptions

The options object that is passed into the Chart.js chart (more info)

plugins

Type: Chart.PluginServiceRegistrationOptions[]

The plugins array that is passed into the Chart.js chart (more info)

getDatasetAtEvent

Type: (dataset: Array<{}>, event: React.MouseEvent<HTMLCanvasElement>) => void Default: undefined

Proxy for Chart.js getDatasetAtEvent. Calls with dataset and triggering event

getElementAtEvent

Type: (element: [{}], event: React.MouseEvent<HTMLCanvasElement>) => void Default: undefined

Proxy for Chart.js getElementAtEvent. Calls with single element array and triggering event

getElementsAtEvent

Type: (elements: Array<{}>, event: React.MouseEvent<HTMLCanvasElement>) => void Default: undefined

Proxy for Chart.js getElementsAtEvent. Calls with element array and triggering event

FAQ

Why doesn't my chart maintain it's width/height?

In order for Chart.js to obey the custom size you need to set maintainAspectRatio to false

<Bar
	data={data}
	width={100}
	height={50}
	options={{ maintainAspectRatio: false }}
/>

How do I access my chart's instance?

The Chart.js instance can be accessed by placing a ref to the element as:

const App => {
  const ref = useRef();

  return <Doughnut ref={ref} data={data} options={options} />;
};

How do I acess the canvas context?

The canvas node and hence context can be accessed within the data function. This approach is useful when you want to keep your components pure.

render() {
  const data = (canvas) => {
    const ctx = canvas.getContext('2d')
    const gradient = ctx.createLinearGradient(0,0,100,0);

    return {
      backgroundColor: gradient
      // ...the rest
    }
  }

  return <Line data={data} />;
}

Additional Information

Defaults

Chart.js defaults can be set by importing the defaults object:

import { defaults } from 'react-chartjs-2';

// Disable animating charts by default.
defaults.animation = false;

If you want to bulk set properties, try using the lodash.merge function. This function will do a deep recursive merge preserving previously set values that you don't want to update.

import { defaults } from 'react-chartjs-2';
import merge from 'lodash.merge';

merge(defaults, {
	animation: false,
  line: {
    borderColor: '#F85F73',
  }
});
``` -->

<!-- ### Chart.js object

You can access the internal Chart.js object to register plugins or extend charts like this:

```JavaScript
import { Chart } from 'react-chartjs-2';

componentWillMount() {
  Chart.register({
    afterDraw: function (chart, easing) {
      // Plugin code.
    }
  });
}

Working with Multiple Datasets

You will find that any event which causes the chart to re-render, such as hover tooltips, etc., will cause the first dataset to be copied over to other datasets, causing your lines and bars to merge together. This is because to track changes in the dataset series, the library needs a key to be specified - if none is found, it can't tell the difference between the datasets while updating. To get around this issue, you can take these two approaches:

1. Add a label property on each dataset. By default, this library uses the label property as the key to distinguish datasets.
2. Specify a different property to be used as a key by passing a datasetKeyProvider prop to your chart component, which would return a unique string value for each dataset.

Development

NOTE: The source code for the component is in src. A transpiled CommonJS version (generated with Babel) is available in dist for use with node.js, browserify and webpack. A UMD bundle is also built to dist, which can be included without the need for any build system.

License

MIT Licensed Copyright (c) 2020 Jeremy Ayerst