feat($compile): Allow using functions as templates in directives

Added dynamic template support in directives:
- The call will pass the element and directive attributes as parameters
- This allows generating templates on the fly
- It also applies to templateUrl

Author: lrlopez

docs/content/guide/directive.ngdoc

@@ -377,11 +377,15 @@ compiler}. The attributes are:
 
   * `template` - replace the current element with the contents of the HTML. The replacement process
     migrates all of the attributes / classes from the old element to the new one. See Creating
-    Widgets section below for more information.
+    Widgets section below for more information. If the template is a function, it will be called
+    with the current elementa normalized list of attributes (see 
+    {@link guide/directive#Attributes Attributes}). The content returned by the call will be the
+    template to be compiled.
 
   * `templateUrl` - Same as `template` but the template is loaded from the specified URL. Because
     the template loading is asynchronous the compilation/linking is suspended until the template
-    is loaded.
+    is loaded. You can also use a function that will return the URL to load. The call will include
+    the current element and the normalized list of attributes as a single parameter.
 
   * `replace` - if set to `true` then the template will replace the current element, rather than
     append the template to the element.

src/ng/compile.js

@@ -649,6 +649,9 @@ function $CompileProvider($provide) {
         if ((directiveValue = directive.template)) {
           assertNoDuplicate('template', templateDirective, directive, $compileNode);
           templateDirective = directive;
+          if (isFunction(directive.template)) {
+              directiveValue = directive.template($compileNode, templateAttrs);
+          }
           directiveValue = denormalizeTemplate(directiveValue);
 
           if (directive.replace) {
@@ -967,11 +970,19 @@ function $CompileProvider($provide) {
           // The fact that we have to copy and patch the directive seems wrong!
           derivedSyncDirective = extend({}, origAsyncDirective, {
             controller: null, templateUrl: null, transclude: null, scope: null
-          });
+          }),
+          urlToLoad;
 
       $compileNode.html('');
 
-      $http.get(origAsyncDirective.templateUrl, {cache: $templateCache}).
+      if (isFunction(origAsyncDirective.templateUrl)) {
+        urlToLoad = origAsyncDirective.templateUrl($compileNode, tAttrs);
+      }
+      else {
+        urlToLoad = origAsyncDirective.templateUrl;
+      }
+
+      $http.get(urlToLoad, {cache: $templateCache}).
         success(function(content) {
           var compileNode, tempTemplateAttrs, $template;
 

test/ng/compileSpec.js

@@ -625,6 +625,50 @@ describe('$compile', function() {
       });
 
 
+      describe('template function', function() {
+
+        beforeEach(module(function() {
+          directive('replace', valueFn({
+            restrict: 'CAM',
+            replace: true,
+            template: function(e,f) {
+              return '<div class="log" style="width: 10px" high-log>Replace!</div>'
+            }, 
+            compile: function(element, attr) {
+              attr.$set('compiled', 'COMPILED');
+              expect(element).toBe(attr.$$element);
+            }
+          }));
+
+          directive('replaceattr', valueFn({
+            restrict: 'CAM',
+            replace: true,
+            template: function(e,f) {
+              expect(isElement(e)).toBeTruthy();
+              return '<div class="log" style="width: 10px" high-log ' + f.myattr + '="123">Replace!</div>'
+            }, 
+            compile: function(element, attr) {
+              expect(attr.dynamic).toBe('123');
+              attr.$set('dynamic', '456');
+            }
+          }));
+        }));
+
+
+        it('should replace element with template returned by function', inject(function($compile, $rootScope) {
+          element = $compile('<div><div replace>ignore</div><div>')($rootScope);
+          expect(element.text()).toEqual('Replace!');
+          expect(element.find('div').attr('compiled')).toEqual('COMPILED');
+        }));
+
+        it('should pass element and attributes to template function', inject(function($compile, $rootScope) {
+          element = $compile('<div><div replaceattr myattr="dynamic">ignore</div><div>')($rootScope);
+          expect(element.text()).toEqual('Replace!');
+          expect(element.find('div').attr('dynamic')).toEqual('456');
+        }));
+      });
+
+
       describe('templateUrl', function() {
 
         beforeEach(module(
@@ -1155,6 +1199,54 @@ describe('$compile', function() {
         });
       });
 
+      describe('templateUrl function', function() {
+
+        beforeEach(module(
+          function() {
+            directive('hello', valueFn({
+              restrict: 'CAM', templateUrl: function(e,t) {
+                return 'hello.html';
+              },
+              transclude: true
+            }));
+            directive('cau', valueFn({
+              restrict: 'CAM', templateUrl: function(e,t) {
+                expect(isElement(e)).toBeTruthy();
+                return 'cau'+t.test+'.html';
+              }
+            }));
+          }
+        ));
+
+        it('should compile, link and flush the template inline when using functions as templateUrl', inject(
+            function($compile, $templateCache, $rootScope) {
+              $templateCache.put('hello.html', '<span>Hello, {{name}}!</span>');
+              $rootScope.name = 'Elvis';
+              element = $compile('<div><b hello></b></div>')($rootScope);
+
+              $rootScope.$digest();
+
+              expect(sortedHtml(element)).
+                  toEqual('<div><b><span>Hello, Elvis!</span></b></div>');
+            }
+        ));
+
+        it('should pass element and attributes to the templateUrl function', inject(
+            function($compile, $templateCache, $rootScope) {
+              $templateCache.put('cau2.html', '<span>Hey, {{name}}!</span>');
+              $templateCache.put('cau3.html', '<span>Say: Hey, {{name}}!</span>');
+              $rootScope.name = 'me';
+              element = $compile('<div><b cau test="2"></b><b cau test="3"></b></div>')($rootScope);
+
+              $rootScope.$digest();
+
+              expect(sortedHtml(element)).
+                  toEqual('<div><b test="2"><span>Hey, me!</span></b><b test="3">' +
+                      '<span>Say: Hey, me!</span></b></div>');
+            }
+        ));
+      });
+
 
       describe('scope', function() {
         var iscope;