There have always been problems with the library I implemented for the InputMask. It just has to many bugs in them, especially with the placeholder and how the cursor behaves. (I think as of today it has 450+ open issues on github). And the mask syntax is just horrible. But 4 years ago, this was about the best one around. There are plans to completely replace it in a future version with another one (if I can find a good one, but even now in 2020, this one seems to be the best one around). In the mean time, I thing B4JS 'may' be helpful here, but it will not be easy to write.