fix(typeahead): timeout cancellation when deleting characters

Closes #2074

Author: Michal Wesolowski

src/typeahead/test/typeahead.spec.js

@@ -555,6 +555,21 @@ describe('typeahead tests', function () {
       expect($scope.isLoading).toBeFalsy();
     });
 
+    it('should cancel old timeout when deleting characters', inject(function ($timeout) {
+      var values = [];
+      $scope.loadMatches = function(viewValue) {
+        values.push(viewValue);
+        return $scope.source;
+      };
+      var element = prepareInputEl('<div><input ng-model="result" typeahead="item for item in loadMatches($viewValue) | filter:$viewValue" typeahead-min-length="2" typeahead-wait-ms="200"></div>');
+      changeInputValueTo(element, 'match');
+      changeInputValueTo(element, 'm');
+
+      $timeout.flush();
+
+      expect(values).not.toContain('match');
+    }));
+
     it('does not close matches popup on click in input', function () {
       var element = prepareInputEl('<div><input ng-model="result" typeahead="item for item in source | filter:$viewValue"></div>');
       var inputEl = findInput(element);

src/typeahead/typeahead.js

@@ -173,6 +173,18 @@ angular.module('ui.bootstrap.typeahead', ['ui.bootstrap.position', 'ui.bootstrap
       //Declare the timeout promise var outside the function scope so that stacked calls can be cancelled later 
       var timeoutPromise;
 
+      var scheduleSearchWithTimeout = function(inputValue) {
+        timeoutPromise = $timeout(function () {
+          getMatchesAsync(inputValue);
+        }, waitTime);
+      };
+
+      var cancelPreviousTimeout = function() {
+        if (timeoutPromise) {
+          $timeout.cancel(timeoutPromise);
+        }
+      };
+
       //plug into $parsers pipeline to open a typeahead on view changes initiated from DOM
       //$parsers kick-in on all the changes coming from the view as well as manually triggered by $setViewValue
       modelCtrl.$parsers.unshift(function (inputValue) {
@@ -181,17 +193,14 @@ angular.module('ui.bootstrap.typeahead', ['ui.bootstrap.position', 'ui.bootstrap
 
         if (inputValue && inputValue.length >= minSearch) {
           if (waitTime > 0) {
-            if (timeoutPromise) {
-              $timeout.cancel(timeoutPromise);//cancel previous timeout
-            }
-            timeoutPromise = $timeout(function () {
-              getMatchesAsync(inputValue);
-            }, waitTime);
+            cancelPreviousTimeout();
+            scheduleSearchWithTimeout(inputValue);
           } else {
             getMatchesAsync(inputValue);
           }
         } else {
           isLoadingSetter(originalScope, false);
+          cancelPreviousTimeout();
           resetMatches();
         }