My definition of input masking:
Formatting of user-input in an
<input>element as it is provided, into a preset shape/structure
For example, here is a set of phone inputs that have masks setup:
This CSS-Tricks link showcases some examples as well as some libraries, but I'm interested in what the DEV community uses nowadays (that post is ~2 years old).
Bonus points if the library is framework agnostic, i.e. does not use jQuery, Angular, React, Vue, etc.