AngularFire $add—TypeError: undefined is not a function
问题 When I try to substitute $add for push, I get this error. TypeError: undefined is not a function at Scope.$scope.sendComment (http://localhost:9000/scripts/controllers/post.js:22:38) at http://localhost:9000/bower_components/angular/angular.js:10847:21 ... Here's my controller @ post.js 16 $scope.sendComment = function () { 17 var newComment = { 18 user: $scope.currentUser, 19 text: $scope.currentText 20 21 }; 22 var promise = CommentService.add(newComment); 23 promise.then(function(name) {