JarCasting
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;
fallbackContent?: React.ReactNode;
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)
fallbackContent
Type: React.ReactNode
A fallback for when the canvas cannot be rendered. Can be used for accessible chart descriptions (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:
- Add a
labelproperty on each dataset. By default, this library uses thelabelproperty as the key to distinguish datasets. - Specify a different property to be used as a key by passing a
datasetKeyProviderprop 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