How to rewrite swal prompt without using promises

Question

I want to have a prompt option for my alert before deleting an item. However it does not work in IE. How can I avoid using this promise (.then()) ?

The example from swal is this:

swal({
  title: "Are you sure?",
  text: "Once deleted, you will not be able to recover this imaginary file!",
  icon: "warning",
  buttons: true,
  dangerMode: true,
})
.then((willDelete) => {
  if (willDelete) {
    swal("Poof! Your imaginary file has been deleted!", {
      icon: "success",
    });
  } else {
    swal("Your imaginary file is safe!");
  }
});

Answer 1

Assuming that the rest of swal works on IE (have you checked?), then you'll need to:

1. Add a Promise polyfill, of which there are many easily come by, and

2. Not use arrow functions, since arrow functions aren't supported by IE

For instance, with a Promise polyfill, this is valid code for IE:

swal({
  title: "Are you sure?",
  text: "Once deleted, you will not be able to recover this imaginary file!",
  icon: "warning",
  buttons: true,
  dangerMode: true,
})
.then(function(willDelete) { // <=== Only change is here
  if (willDelete) {
    swal("Poof! Your imaginary file has been deleted!", {
      icon: "success",
    });
  } else {
    swal("Your imaginary file is safe!");
  }
});

---

Or you can use a tool like Babel that transpiles ES2015+ code to be ES5-compatible and can optionally include polyfills (for things like Promise). Babel would handle converting arrow functions for you.