perf(jqLite): implement and use the `empty` method in place of `html(‘’)`

jQuery's elem.html('') is way slower than elem.empty(). As clearing
element contents happens quite often in certain scenarios, switching
to using .empty() provides a significant performance boost when using
Angular with jQuery.

Closes #4457

3 files changed, 9 insertions, 9 deletions

diff --git a/test/ng/compileSpec.js b/test/ng/compileSpec.js
index 853290a6..1b98cd58 100755
--- a/test/ng/compileSpec.js
+++ b/test/ng/compileSpec.js
@@ -170,26 +170,26 @@ describe('$compile', function() {
       // First with only elements at the top level
       element = jqLite('<div><div></div></div>');
       $compile(element.contents())($rootScope);
-      element.html('');
+      element.empty();
       expect(calcCacheSize()).toEqual(0);
 
       // Next with non-empty text nodes at the top level
       // (in this case the compiler will wrap them in a <span>)
       element = jqLite('<div>xxx</div>');
       $compile(element.contents())($rootScope);
-      element.html('');
+      element.empty();
       expect(calcCacheSize()).toEqual(0);
 
       // Next with comment nodes at the top level
       element = jqLite('<div><!-- comment --></div>');
       $compile(element.contents())($rootScope);
-      element.html('');
+      element.empty();
       expect(calcCacheSize()).toEqual(0);
 
       // Finally with empty text nodes at the top level
       element = jqLite('<div>   \n<div></div>   </div>');
       $compile(element.contents())($rootScope);
-      element.html('');
+      element.empty();
       expect(calcCacheSize()).toEqual(0);
     });
 
diff --git a/test/ng/directive/formSpec.js b/test/ng/directive/formSpec.js
index 77beb2fd..dde6f0a0 100644
--- a/test/ng/directive/formSpec.js
+++ b/test/ng/directive/formSpec.js
@@ -216,7 +216,7 @@ describe('form', function() {
         // yes, I know, scope methods should not do direct DOM manipulation, but I wanted to keep
         // this test small. Imagine that the destroy action will cause a model change (e.g.
         // $location change) that will cause some directive to destroy the dom (e.g. ngView+$route)
-        doc.html('');
+        doc.empty();
         destroyed = true;
       }
 
diff --git a/test/ng/directive/ngIncludeSpec.js b/test/ng/directive/ngIncludeSpec.js
index 9e0a47b0..79e7f312 100644
--- a/test/ng/directive/ngIncludeSpec.js
+++ b/test/ng/directive/ngIncludeSpec.js
@@ -47,7 +47,7 @@ describe('ngInclude', function() {
     $rootScope.url = 'myUrl';
     $rootScope.$digest();
     expect(body.text()).toEqual('misko');
-    body.html('');
+    body.empty();
   }));
 
 
@@ -60,7 +60,7 @@ describe('ngInclude', function() {
     $rootScope.url = 'myUrl';
     $rootScope.$digest();
     expect(element.text()).toEqual('Alibaba');
-    jqLite(document.body).html('');
+    jqLite(document.body).empty();
   }));
 
 
@@ -74,7 +74,7 @@ describe('ngInclude', function() {
     expect(function() { $rootScope.$digest(); }).toThrowMinErr(
         '$sce', 'insecurl',
         /Blocked loading resource from url not allowed by \$sceDelegate policy.  URL: http:\/\/example.com\/myUrl.*/);
-    jqLite(document.body).html('');
+    jqLite(document.body).empty();
   }));
 
 
@@ -88,7 +88,7 @@ describe('ngInclude', function() {
     expect(function() { $rootScope.$digest(); }).toThrowMinErr(
         '$sce', 'insecurl',
         /Blocked loading resource from url not allowed by \$sceDelegate policy.  URL: http:\/\/example.com\/myUrl.*/);
-    jqLite(document.body).html('');
+    jqLite(document.body).empty();
   }));