Canvas download

import React from "react";
import Barcode from "react-barcode";

const saveImage = () => {
    const canvas = document.getElementById("canvas");
    var dataUrl = canvas.toDataURL();
    download(dataUrl);
};

const download = (source, filename = "image.png") => {
    const element = document.createElement("a");
    element.setAttribute("href", source);
    element.setAttribute("download", filename);

    element.style.display = "none";
    document.body.appendChild(element);
    element.click();
    document.body.removeChild(element);
};

const draw = () => {
    const canvas = document.getElementById("canvas");
    if (canvas.getContext) {
        const ctx = canvas.getContext("2d");

        ctx.fillRect(25, 25, 100, 100);
        ctx.clearRect(45, 45, 60, 60);
        ctx.strokeRect(50, 50, 50, 50);
    }
};

class App extends React.Component {
    componentDidMount() {
        draw();
        saveImage();
    }

    render() {
        return (<div>
            <canvas id="canvas" width="150" height="150"></canvas>
        </div>);
    }
}

export default App;