Uncaught ReferenceError: Swal is not defined at HTMLSpanElement.copy.onclick

[liulyxandy-codemao]

copy.onclick = function () {
var code = Blockly.JavaScript.workspaceToCode(workspace);
navigator.clipboard.writeText(code);
//here's the error
Swal.fire({
position: 'top-end',
type: 'success',
title: 'Copied',
showConfirmButton: false,
timer: 1500
})
}

Hello,

I don't know why I am getting error here, can you help me?

Thanks.