React - Simple example

info

The following only describes a relatively simple example that only renders an area series that could be tweaked to render any other type of series.

For a more complete scenario where you could wrap Lightweight Charts™ into a component having sub components, please consult this example.

On this page you will learn how to easily use Lightweight Charts™ with React.

Preparing your project

For the example purpose we are using Parcel starter kit but feel free to use any other tool or starter kit.

git clone git@github.com:brandiqa/react-parcel-starter.git lwc-react
cd lwc-react
npm install

To run your project simply

npm start

This will create a web page accessible by default on http://localhost:1234.

Creating a charting component

The example React component on this page may not fit your requirements completely. Creating a general purpose declarative wrapper for Lightweight Charts™ imperative API is a challenge, but hopefully you can adapt this example to your use case.

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For this example we are using props to set chart colors based on the current theme (light or dark). In your real code it might be a better idea to use a Context.

import { AreaSeries, createChart, ColorType } from 'lightweight-charts';
import React, { useEffect, useRef } from 'react';

export const ChartComponent = props => {
    const {
        data,
        colors: {
            backgroundColor = 'white',
            lineColor = '#2962FF',
            textColor = 'black',
            areaTopColor = '#2962FF',
            areaBottomColor = 'rgba(41, 98, 255, 0.28)',
        } = {},
    } = props;

    const chartContainerRef = useRef();

    useEffect(
        () => {
            const handleResize = () => {
                chart.applyOptions({ width: chartContainerRef.current.clientWidth });
            };

            const chart = createChart(chartContainerRef.current, {
                layout: {
                    background: { type: ColorType.Solid, color: backgroundColor },
                    textColor,
                },
                width: chartContainerRef.current.clientWidth,
                height: 300,
            });
            chart.timeScale().fitContent();

            const newSeries = chart.addSeries(AreaSeries, { lineColor, topColor: areaTopColor, bottomColor: areaBottomColor });
            newSeries.setData(data);

            window.addEventListener('resize', handleResize);

            return () => {
                window.removeEventListener('resize', handleResize);

                chart.remove();
            };
        },
        [data, backgroundColor, lineColor, textColor, areaTopColor, areaBottomColor]
    );

    return (
        <div
            ref={chartContainerRef}
        />
    );
};

const initialData = [
    { time: '2018-12-22', value: 32.51 },
    { time: '2018-12-23', value: 31.11 },
    { time: '2018-12-24', value: 27.02 },
    { time: '2018-12-25', value: 27.32 },
    { time: '2018-12-26', value: 25.17 },
    { time: '2018-12-27', value: 28.89 },
    { time: '2018-12-28', value: 25.46 },
    { time: '2018-12-29', value: 23.92 },
    { time: '2018-12-30', value: 22.68 },
    { time: '2018-12-31', value: 22.67 },
];

export function App(props) {
    return (
        <ChartComponent {...props} data={initialData}></ChartComponent>
    );
}

and you'll have a reusable component that could then be enhanced, tweaked to meet your needs, adding properties and even functionalities.

If you've successfully followed all the steps you should see something similar to