Secure text with last character visible

[dicash]

What problem you are trying to solve?
At the moment we have displayChar, allowing to hide characters that are not supposed to be visible.

IMask(element, {
  mask: '000000',
  displayChar: '•',
  lazy: false,
  overwrite: 'shift',
})

New requirement that we have is displaying last input character as visible, like it does iOS.

Describe the solution you'd like
Some option to display last character, or maybe allow passing displayChar a function, so that we can decide which char should be visible which shouldn't.

Describe alternatives you've considered
Are there alternatives?

[uNmAnNeR]

hi. yes, you can change mask displayChar depending on the input value + set a timeout