Protect against unknown emojis in frequently used list

See https://gitlab.slack.com/archives/frontend/p1489690607738864

2 files changed, 26 insertions, 4 deletions

diff --git a/app/assets/javascripts/behaviors/gl_emoji.js b/app/assets/javascripts/behaviors/gl_emoji.js
index 59741cc9b1a..19a607309e4 100644
--- a/app/assets/javascripts/behaviors/gl_emoji.js
+++ b/app/assets/javascripts/behaviors/gl_emoji.js
@@ -13,9 +13,14 @@ function emojiImageTag(name, src) {
 }
 
 function assembleFallbackImageSrc(inputName) {
-  const name = Object.prototype.hasOwnProperty.call(emojiAliases, inputName) ?
+  let name = Object.prototype.hasOwnProperty.call(emojiAliases, inputName) ?
     emojiAliases[inputName] : inputName;
-  const emojiInfo = emojiMap[name];
+  let emojiInfo = emojiMap[name];
+  // Fallback to question mark for unknown emojis
+  if (!emojiInfo) {
+    name = 'grey_question';
+    emojiInfo = emojiMap[name];
+  }
   const fallbackImageSrc = `${gon.asset_host || ''}${gon.relative_url_root || ''}/assets/emoji/${name}-${emojiInfo.digest}.png`;
 
   return fallbackImageSrc;
@@ -26,9 +31,15 @@ const glEmojiTagDefaults = {
 };
 function glEmojiTag(inputName, options) {
   const opts = Object.assign({}, glEmojiTagDefaults, options);
-  const name = Object.prototype.hasOwnProperty.call(emojiAliases, inputName) ?
+  let name = Object.prototype.hasOwnProperty.call(emojiAliases, inputName) ?
     emojiAliases[inputName] : inputName;
-  const emojiInfo = emojiMap[name];
+  let emojiInfo = emojiMap[name];
+  // Fallback to question mark for unknown emojis
+  if (!emojiInfo) {
+    name = 'grey_question';
+    emojiInfo = emojiMap[name];
+  }
+
   const fallbackImageSrc = assembleFallbackImageSrc(name);
   const fallbackSpriteClass = `emoji-${name}`;
 
diff --git a/app/assets/javascripts/behaviors/gl_emoji/is_emoji_name_valid.js b/app/assets/javascripts/behaviors/gl_emoji/is_emoji_name_valid.js
new file mode 100644
index 00000000000..be4aeb32c46
--- /dev/null
+++ b/app/assets/javascripts/behaviors/gl_emoji/is_emoji_name_valid.js
@@ -0,0 +1,11 @@
+import emojiMap from 'emojis/digests.json';
+import emojiAliases from 'emojis/aliases.json';
+
+function isEmojiNameValid(inputName) {
+  const name = Object.prototype.hasOwnProperty.call(emojiAliases, inputName) ?
+    emojiAliases[inputName] : inputName;
+
+  return name && emojiMap[name];
+}
+
+export default isEmojiNameValid;