Капитал Первая буква реагирует
let fLCapital = s => s = s.charAt(0).toUpperCase() + s.slice(1);
fLCapital('this is a test') // "This is a test"
Inquisitive Iguana
let fLCapital = s => s = s.charAt(0).toUpperCase() + s.slice(1);
fLCapital('this is a test') // "This is a test"<Text>{str.charAt(0).toUpperCase() + str.slice(1);}</Text>
// I think the best way is to do it using styles (it will work for any UI framework)
// JS
<Text class="capitalize-me">sometext</Text>
// CSS
.capitalize-me::first-letter {
text-transform: capitalize;
}