Angularjs - ng-click function vs directive

问题:

I can't decide which method to use in following case. I'm trying to alert when clicking on buttons. I can do this using 2 methods. Which is the best practice and please tell me why?

Method 1

<div ng-app="app">
  <button alert>directive</button>
</div>

---

var app = angular.module('app', ['ngRoute']);

app
  .directive('alert', function(){
    return {

      link: function(scope, element, attr) {
            element.on('click', function(){
          alert('clicked');
        })
      }

    }
  })

Method 2

<div ng-app="app" ng-controller="MainCtrl">
  <button ng-click="go()">ng-click</button>  
</div>

---

app.controller('MainCtrl', ['$scope', function($scope) {

  $scope.go = function() {
    alert('clicked');
  }
}]);

Thank you, Rushan

回答1:

Let me explain it to you using example.

HTML

<div ng-app="myapp">
    <div ng-controller="MyCtrl1">
        <button ng-click="showAlert('hello')">Fist</button>
        <button ng-click="showConsole('hello')">for Fist one only</button>
        <button show-alert="first using directive">Fist with directive</button>
    </div>
    <div ng-controller="MyCtrl2">
        <button ng-click="showAlert('hello second')">Second</button>
        <button show-alert="first using directive">Second With directive</button>
    </div>
    <div ng-controller="MyCtrl3">
        <button ng-click="showAlert('hello third')">Third</button>
        <button show-alert="third using directive">third with directive</button>
    </div>
 </div>

JS

var myApp = angular.module('myapp',[]);

myApp
    .controller('MyCtrl1', function ($scope) {
        $scope.showAlert = function (msg) {
            alert(msg);
        };
        $scope.showConsole = function (msg) {
            console.log(msg);
        };
    })
    .controller('MyCtrl2', function ($scope) {
        $scope.showAlert = function (msg) {
            alert(msg);
        };

    })
    .controller('MyCtrl3', function ($scope) {
        $scope.showAlert = function (msg) {
            alert(msg);
        };        
    })
    .directive('showAlert', function(){
        return{
            restrict: 'A',
            link: function(scope, ele, attr){
                var eventName = attr.evetName || 'click';
                var mas = attr.showAlert || 'just alert';
                ele.on(eventName, function(){
                   alert(mas); 
                });
            }
        };
    });

JsFiddleLink

As you can see in the example show-alert="[MSG]" was able to reduce code replication compared to directly using $scope.showAlert in each controller. so in this case creating directive was better.

But, in case of $scope.showConsole was used only once, we are not reusing it anywhere. so its fine to use it directly inside controller.

Even though. you can also create directive for showConsole functionality, if you feel like in future it will be used somewhere else also. its totally fine. this decisions totally depends on the what use-case you have.

回答2:

If all elements have to run the same function on click event, making it a directive is a good idea. Otherwise use ngClick. Creating a directive and then passing a click handler function is reimplemeting the same thing.