diff --git a/app/assets/javascripts/discourse/lib/autocomplete.js.es6 b/app/assets/javascripts/discourse/lib/autocomplete.js.es6
index 71dce2d1d68..5da0fb6b02f 100644
--- a/app/assets/javascripts/discourse/lib/autocomplete.js.es6
+++ b/app/assets/javascripts/discourse/lib/autocomplete.js.es6
@@ -242,6 +242,15 @@ export default function(options) {
     });
   };
 
+  const dataSource = (term, opts) => {
+    if (term.length !== 0 && term.trim().length === 0) {
+      closeAutocomplete();
+      return null;
+    } else {
+      return opts.dataSource(term);
+    }
+  };
+
   var updateAutoComplete = function(r) {
 
     if (completeStart === null) return;
@@ -304,13 +313,13 @@ export default function(options) {
       var prevChar = me.val().charAt(caretPosition - 1);
       if (checkTriggerRule() && (!prevChar || allowedLettersRegex.test(prevChar))) {
         completeStart = completeEnd = caretPosition;
-        updateAutoComplete(options.dataSource(""));
+        updateAutoComplete(dataSource("", options));
       }
     } else if ((completeStart !== null) && (e.charCode !== 0)) {
       caretPosition = Discourse.Utilities.caretPosition(me[0]);
       term = me.val().substring(completeStart + (options.key ? 1 : 0), caretPosition);
       term += String.fromCharCode(e.charCode);
-      updateAutoComplete(options.dataSource(term));
+      updateAutoComplete(dataSource(term, options));
     }
   });
 
@@ -360,7 +369,7 @@ export default function(options) {
             completeStart = c;
             caretPosition = completeEnd = initial;
             term = me[0].value.substring(c + 1, initial);
-            updateAutoComplete(options.dataSource(term));
+            updateAutoComplete(dataSource(term, options));
             return true;
           }
         }
@@ -444,7 +453,7 @@ export default function(options) {
             closeAutocomplete();
           }
 
-          updateAutoComplete(options.dataSource(term));
+          updateAutoComplete(dataSource(term, options));
           return true;
         default:
           completeEnd = caretPosition;