Properly guard generating thread meta images

src/helpers/generate-image-from-text.js

@@ -38,10 +38,13 @@ type GetMetaImageInput = {
   footer: string,
 };
 
-const generateImageFromText = ({ title, footer }: GetMetaImageInput) => {
+const generateImageFromText = ({
+  title,
+  footer,
+}: GetMetaImageInput): ?string => {
   const base64title = btoa(title);
   const base64footer = btoa(footer);
-  if (!base64title || !base64footer) return;
+  if (!base64title || !base64footer) return null;
 
   const titleUrl = `${IMGIX_TEXT_ENDPOINT}?${stringify(
     { ...TITLE_PARAMS, txt64: base64title.replace(/=/g, '') },
@@ -55,7 +58,7 @@ const generateImageFromText = ({ title, footer }: GetMetaImageInput) => {
   const base64titleurl = btoa(titleUrl);
   const base64footerurl = btoa(footerUrl);
 
-  if (!base64titleurl || !base64footerurl) return;
+  if (!base64titleurl || !base64footerurl) return null;
 
   const BACKGROUND_PARAMS = {
     w: WIDTH,

src/views/thread/container.js

@@ -433,6 +433,12 @@ class ThreadContainer extends React.Component<Props, State> {
       const headDescription = isWatercooler
         ? `Watercooler chat for the ${thread.community.name} community`
         : description;
+      const metaImage = generateImageFromText({
+        title: isWatercooler
+          ? `Chat with the ${thread.community.name} community`
+          : thread.content.title,
+        footer: `spectrum.chat/${thread.community.slug}`,
+      });
 
       return (
         <ErrorBoundary>
@@ -458,14 +464,11 @@ class ThreadContainer extends React.Component<Props, State> {
                 title={headTitle}
                 description={headDescription}
                 type="article"
-                image={generateImageFromText({
-                  title: isWatercooler
-                    ? `Chat with the ${thread.community.name} community`
-                    : thread.content.title,
-                  footer: `spectrum.chat/${thread.community.slug}`,
-                })}
+                image={metaImage}
               >
-                <meta name="twitter:card" content="summary_large_image" />
+                {metaImage && (
+                  <meta name="twitter:card" content="summary_large_image" />
+                )}
                 <meta
                   property="article:published_time"
                   content={new Date(thread.createdAt).toISOString()}