Convert remaining components to TypeScript.

src/components/fab/index.tsx

@@ -0,0 +1,39 @@
+import { h, Component } from 'preact';
+import Icon from 'preact-material-components/Icon';
+import 'preact-material-components/Icon/style.css';
+import Fab from 'preact-material-components/Fab';
+import RadialProgress from 'material-radial-progress';
+import * as style from './style.scss';
+
+type Props = {
+	showing: boolean
+};
+type State = {
+	loading: boolean
+};
+
+export default class AppFab extends Component<Props, State> {
+	state: State = {
+		loading: false
+	};
+
+	handleClick = () => {
+		console.log('TODO: Save the file to disk.');
+		this.setState({ loading: true });
+		setTimeout( () => {
+			this.setState({ loading: false });
+		}, 1000);
+	};
+
+	render({ showing }, { loading }) {
+		return (
+			<Fab ripple secondary exited={showing===false} class={style.fab} onClick={this.handleClick}>
+				{ loading ? (
+					<RadialProgress primary class={style.progress} />
+				) : (
+					<Icon>file_download</Icon>
+				) }
+			</Fab>
+		);
+	}
+}