[2.2.x] Fixed #29825 -- Fixed JS ngettext if the string is a non-plural msgid in the catalog.

Backport of 16454ac35f from master.

django/views/i18n.py

@@ -113,7 +113,7 @@ js_catalog_template = r"""
       if (typeof(value) == 'undefined') {
         return (count == 1) ? singular : plural;
       } else {
-        return value[django.pluralidx(count)];
+        return value.constructor === Array ? value[django.pluralidx(count)] : value;
       }
     };
 

tests/view_tests/locale/de/LC_MESSAGES/djangojs.po

@@ -39,3 +39,6 @@ msgid "%s result"
 msgid_plural "%s results"
 msgstr[0] "%s Resultat"
 msgstr[1] "%s Resultate"
+
+msgid "Image"
+msgstr "Bild"

tests/view_tests/templates/jsi18n.html

@@ -30,6 +30,13 @@
     </script>
   </p>
 
+  <p id="ngettext_onnonplural">
+      <!-- The po file only contains the non plural "Image" string. -->
+      <script type="text/javascript">
+          document.write(interpolate(ngettext("Image", "Images", 5), [1]));
+      </script>
+  </p>
+
   <p id="pgettext">
     <script type="text/javascript">
     document.write(pgettext("verb", "May"));

tests/view_tests/tests/test_i18n.py

@@ -435,6 +435,8 @@ class I18nSeleniumTests(SeleniumTestCase):
         self.assertEqual(elem.text, "1 Element")
         elem = self.selenium.find_element_by_id("ngettext_plur")
         self.assertEqual(elem.text, "455 Elemente")
+        elem = self.selenium.find_element_by_id("ngettext_onnonplural")
+        self.assertEqual(elem.text, "Bild")
         elem = self.selenium.find_element_by_id("pgettext")
         self.assertEqual(elem.text, "Kann")
         elem = self.selenium.find_element_by_id("npgettext_sing")