An example would be really helpful, for example (adapted from the old code):

```
\dontrun{
# Register an input handler which rounds a input number to the nearest integer
registerInputHandler("mypackage.validint", function(x, shinysession, name) {
  if (is.null(x)) return(NA)
  round(x)
})


## On the Javascript side, the associated input binding must have a corresponding getType method:
  getType: function(el) {
    return "mypackage.validint";
  }

}
```