The TextItem has property isVisible and you can use it in the value script something like this:
$S{
if (PriorValue == getField("datasource.Field")){
THIS.isVisible = false
} else {
PriorValue = getField("datasource.Field")
}
getField("datasource.Field")
}
In the init script initialize PriorValue like:
var PriorValue = ""