Don't request suggestions for blank queries

src/js/typeahead_view.js

@@ -171,6 +171,10 @@ var TypeaheadView = (function() {
       var that = this,
           query = this.inputView.getQuery();
 
+      if (utils.isBlankString(query)) {
+        return;
+      }
+
       utils.each(this.datasets, function(i, dataset) {
         dataset.getSuggestions(query, function(suggestions) {
           that._renderSuggestions(query, dataset, suggestions);

src/js/utils.js

@@ -9,6 +9,8 @@ var utils = {
     return (/msie [\w.]+/i).test(navigator.userAgent);
   },
 
+  isBlankString: function(str) { return !str || /^\s*$/.test(str); },
+
   isString: function(obj) { return typeof obj === 'string'; },
 
   isNumber: function(obj) { return typeof obj === 'number'; },

test/typeahead_view_spec.js

@@ -180,10 +180,28 @@ describe('TypeaheadView', function() {
       expect(this.dropdownView.clearSuggestions).toHaveBeenCalled();
     });
 
-    it('should call dropdownView.renderSuggestions for each dataset',
-    function() {
-      this.inputView.trigger('queryChange');
-      expect(this.dropdownView.renderSuggestions.callCount).toBe(3);
+    describe('if query is a blank string', function() {
+      beforeEach(function() {
+        this.inputView.getQuery.andReturn('  ');
+        this.inputView.trigger('queryChange');
+      });
+
+      it('should not call dropdownView.renderSuggestions for each dataset',
+      function() {
+        expect(this.dropdownView.renderSuggestions.callCount).toBe(0);
+      });
+    });
+
+    describe('if query is not a blank string', function() {
+      beforeEach(function() {
+        this.inputView.getQuery.andReturn('not blank');
+        this.inputView.trigger('queryChange');
+      });
+
+      it('should call dropdownView.renderSuggestions for each dataset',
+      function() {
+        expect(this.dropdownView.renderSuggestions.callCount).toBe(3);
+      });
     });
 
     describe('if language direction has changed', function() {