<script src="proxy.php?url=https%3A%2F%2Fcdn.rawgit.com%2Fmagicien%2Fundo-canvas%2Fv0.1.3%2Fundo-canvas.js"></script>
<script>
const canvas = document.createElement('canvas')
const context = canvas.getContext('2d')
UndoCanvas.enableUndo(context)

context.strokeStyle = '#ff0000'
context.beginPath()
context.moveTo(0, 0)
context.lineTo(30, 30)
context.closePath()
context.stroke()

context.undo() // erase the line

context.redo() // redraw the line

UndoCanvas.disableUndo(context)
</script>

npm install --save undo-canvas

<script src="proxy.php?url=https%3A%2F%2Fcdn.rawgit.com%2Fmagicien%2Fundo-canvas%2Fv0.1.3%2Fundo-canvas.js"></script>