Return early if browser.theme.onUpdated is undefined (#344)

eoger · May 1, 2018 · 323d8d5 · 323d8d5
1 parent cc216b2
commit 323d8d5
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/src/sidebar/tabcenter.js b/src/sidebar/tabcenter.js
@@ -75,6 +75,9 @@ TabCenter.prototype = {
     }
   },
   set _themeIntegration(enabled) {
+    if (!browser.theme.onUpdated) {
+      return;
+    }
     if (!enabled) {
       this._resetTheme();
       if (browser.theme.onUpdated.hasListener(this._themeListener)) {