make client own package (using create-react-app)

client/src/Preview.js

@@ -0,0 +1,30 @@
+import React from 'react';
+
+export default props => {
+  if (props.pdfIsLoading) {
+    return (
+      <div>Lade...</div>
+    );
+  }
+
+  if (props.pdfError) {
+    return (
+      <div>{props.pdfError}</div>
+    );
+  }
+
+  if (!props.pdfUrl) {
+    return (
+      <div>Knopf drücken dann gibts hier was zu sehen!</div>
+    );
+  }
+
+  const styles = {
+    width: '700px',
+    height: '1050px'
+  };
+
+  return (
+    <embed src={props.pdfUrl} style={styles} type="application/pdf" />
+  );
+};