import thaanaKeyboard
import { thaanaKeyboard } from "../utils/thaanaKeyboard"...
const [name, setName] = useState('')
return (
<input
value={name}
onChange={e=>setName(thaanaKeyboard(e.target.value))}
/>
)
....or
onChange={e=> e.target.value = thaanaKeyboard(e.target.value))}