Ta-da. Back button. (#254)

src/components/compress/index.tsx

@@ -60,6 +60,7 @@ interface EncodedImage {
 interface Props {
   file: File | Fileish;
   showSnack: SnackBarElement['showSnackbar'];
+  onBack: () => void;
 }
 
 interface State {
@@ -415,7 +416,7 @@ export default class Compress extends Component<Props, State> {
     this.setState({ images });
   }
 
-  render({ }: Props, { loading, images, source, mobileView }: State) {
+  render({ onBack }: Props, { loading, images, source, mobileView }: State) {
     const [leftImage, rightImage] = images;
     const [leftImageData, rightImageData] = images.map(i => i.data);
 
@@ -460,6 +461,7 @@ export default class Compress extends Component<Props, State> {
           rightCompressed={rightImageData}
           leftImgContain={leftImage.preprocessorState.resize.fitMethod === 'cover'}
           rightImgContain={rightImage.preprocessorState.resize.fitMethod === 'cover'}
+          onBack={onBack}
         />
         {mobileView
           ? (