import React, { useState } from 'react'; import { BrowserRouter as Router, Switch, Route, } from 'react-router-dom'; import Button from '@material-ui/core/Button'; import NavBar from './components/NavBar'; import ExtensionCard from './components/ExtensionCard'; export default function App() { return ( {/* */} ); } function Extensions() { let mapped; const [extensions, setExtensions] = useState([]); if (extensions.length === 0) { mapped =

wait

; fetch('http://127.0.0.1:4567/api/v1/extensions') .then((response) => response.json()) .then((data) => setExtensions(data)); } else { mapped = extensions.map((it) => ); } return

{mapped}

; } function Home() { return ( ); } function Users() { return

Users

; }