Save all canvas contents on the page to PNG files

save-canvases.js

const canvases = document.querySelectorAll('canvas');
for (let i = 0; i < canvases.length; i++) {
    const canvas = canvases[i];
    const link = document.createElement('a');
    link.download = `canvas-${i}.png`;
    link.href = canvas.toDataURL();
    link.click();
}