Fonts

Custom fonts with One.UI.Fonts and useFonts

Custom fonts under One.UI. Fonts.load loads a map of PostScript name to source; a source is an imported asset or a URI string (a file or https URI on native, a URL on web). Loading a name that is already usable resolves at once, and the promise rejects with the first failure. Fonts.isLoaded synchronously asks the platform whether a name is usable, so it is also true for embedded and system fonts.

import { One } from 'one'

await One.UI.Fonts.load({ Inter: require('./assets/Inter.ttf') })
One.UI.Fonts.isLoaded('Inter') // true

On Android, always key by the file’s PostScript name: the platform exposes no name query, so a wrong key registers silently and a later isLoaded for that key reads true. On web, fonts known at build time belong in CSS @font-face; load is for fonts chosen at runtime.

useFonts loads a map on mount and returns [loaded, error]. It seeds from the platform so a map that is already usable never flashes unloaded. Pass a stable map: the effect runs once, like the familiar font hook.

import { useFonts } from 'one'

function App() {
  const [loaded, error] = useFonts({ Inter: require('./assets/Inter.ttf') })
  if (!loaded) return null
  return <Content />
}