Accessing attributes from an AngularJS directive



0 Answers

Although using '@' is more appropriate than using '=' for your particular scenario, sometimes I use '=' so that I don't have to remember to use attrs.$observe():

<su-label tooltip="field.su_documentation">{{field.su_name}}</su-label>

Directive:

myApp.directive('suLabel', function() {
    return {
        restrict: 'E',
        replace: true,
        transclude: true,
        scope: {
            title: '=tooltip'
        },
        template: '<label><a href="#" rel="tooltip" title="{{title}}" data-placement="right" ng-transclude></a></label>',
        link: function(scope, element, attrs) {
            if (scope.title) {
                element.addClass('tooltip-title');
            }
        },
    }
});

Fiddle.

With '=' we get two-way databinding, so care must be taken to ensure scope.title is not accidentally modified in the directive. The advantage is that during the linking phase, the local scope property (scope.title) is defined.

Question

My AngularJS template contains some custom HTML syntax like:

<su-label tooltip="{{field.su_documentation}}">{{field.su_name}}</su-label>

I created a directive to process it:

.directive('suLabel', function() {
  return {
    restrict: 'E',
    replace: true,
    transclude: true,
    scope: {
      title: '@tooltip'
    },
    template: '<label><a href="#" rel="tooltip" title="{{title}}" data-placement="right" ng-transclude></a></label>',
    link: function(scope, element, attrs) {
      if (attrs.tooltip) {
        element.addClass('tooltip-title');
      }
    },
  }
})

Everything works fine, at the exception of the attrs.tooltip expression, which always returns undefined, even though the tooltip attribute is visible from Google Chrome's JavaScript console when doing a console.log(attrs).

Any suggestion?

UPDATE: A solution was offered by Artem. It consisted in doing this:

link: function(scope, element, attrs) {
  attrs.$observe('tooltip', function(value) {
    if (value) {
      element.addClass('tooltip-title');
    }
  });
}

AngularJS + = bliss




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