examples/with-custom-font/App.js

import { AppLoading } from "expo";
import * as Font from "expo-font";
import React, { useState } from "react";
import { Text, View } from "react-native";

export default function App() {
  let [fontsLoaded] = useFonts({
    "Inter-Black": require("./assets/fonts/Inter-Black.otf"),
    "Inter-SemiBoldItalic":
      "https://rsms.me/inter/font-files/Inter-SemiBoldItalic.otf?v=3.12",
  });

  if (!fontsLoaded) {
    return <AppLoading />;
  }
  return (
    <View style={{ flex: 1, justifyContent: "center", alignItems: "center" }}>
      <Text>Platform Default</Text>
      <Text style={{ fontFamily: "Inter-Black" }}>Inter Black</Text>
      <Text style={{ fontFamily: "Inter-SemiBoldItalic" }}>
        Inter SemiBoldItalic
      </Text>
    </View>
  );
}

function useFonts(fontMap) {
  let [fontsLoaded, setFontsLoaded] = useState(false);
  (async () => {
    await Font.loadAsync(fontMap);
    setFontsLoaded(true);
  })();
  return [fontsLoaded];
}