How to conditionally apply a template via custom Angular directives?

Question

DEMO

Consider the following directive:

angular.module(\'MyApp\').directive(\'maybeLink\', function() {
  return {
    replace: true,
    s         


        

Answer 1

I think this is the cleanest way to inject a dynamic template based on a scope property

angular.module('app')
.directive('dynamic-template', function () {
  return {
    template:'<ng-include src="template"/>',
    restrict: 'E',
    link: function postLink(scope) {
      scope.template = 'views/dynamic-'+scope.type+'.html';
    }
  };
})

Answer 2

You can use ng-if for the same

Below is the working example

Working Demo

Directive Code:

angular.module('MyApp').directive('maybeLink', function() {
  return {
    replace: true,
    scope: {
      maybeLink: '=',
      maybeLinkText: '='
    },
    template: '<span>' + 
              '  <span ng-if="!maybeLink.link" ng-bind-html="text"></span>' +
              '  <a ng-if="maybeLink.link" href="#" ng-bind-html="text"></a>' +
              '</span>',
    controller: function($scope) {
      $scope.text = $scope.maybeLinkText.replace(/\n/g, '<br>');
    }
  }; 
});

Answer 3

The following is a solution that provides dynamic updates. Usage:

<a rewrite-as-span="true"></a>

<a rewrite-as-span="false"></a>

<a rewrite-as-span="yourFn()"></a>

etc.

app.directive('rewriteAsSpan', function($compile){
  return {
    restrict: 'A',
    template: '<span />',
    replace: true,

    // we transclude the element because when it gets replaced with the span
    // we want all the properties from the original element
    transclude: 'element',

    compile: function(tElement, tAttrs){

      return {
        post: function(scope, element, attrs, controller, transclude){
          var rewrittenEl, originalEl;

          transclude(scope, function(clone){
            originalEl = clone;
          });


          scope.$watch(attrs.rewriteAsSpan, function(value){
            if (value === undefined || value === true){
              if (!rewrittenEl){
                // lazy compile and cache the rewritten element
                transclude(scope, function(clone){
                  rewrittenEl = tElement;
                  rewrittenEl.html(clone.html());
                  // remove this directive because the $compile would get infinite
                  rewrittenEl.removeAttr('rewrite-as-span');
                  $compile(rewrittenEl)(scope);
                });

              }

              element.replaceWith(rewrittenEl);
              element = rewrittenEl;

            } else {
              element.replaceWith(originalEl);
              element = originalEl;
            }
          });

        }
      };
    }
  };
});

Code and specs as a gist

Answer 4

I came up with the following version at the end:

angular.module('MyApp').directive('maybeLink', function($compile) {
  return {
    scope: {
      maybeLink: '=',
      maybeLinkText: '='
    },
    link: function(scope, element, attrs) {
      scope.$watch('maybeLinkText', function(newText) {
        scope.text = newText.replace(/\n/g, '<br>');
      });

      scope.$watch('maybeLink', function() {
        var newElement;

        if (scope.maybeLink) {
          newElement = $compile('<a href="#" ng-bind-html="text"></a>')(scope);
        } else {
          newElement = $compile('<span ng-bind-html="text"></span>')(scope);
        }

        element.replaceWith(newElement); // Replace the DOM
        element = newElement;            // Replace the 'element' reference
      });
    }
  };
});

Answer 5

You might be able to use a template function. According to the docs:

You can specify template as a string representing the template or as a function which takes two arguments tElement and tAttrs (described in the compile function api below) and returns a string value representing the template.

---

function resolveTemplate(tElement, tAttrs) {

}

angular.module('MyApp').directive('maybeLink', function() {
  return {
    //...
    template: resolveTemplate,
    //...
  }; 
});

Answer 6

I would use ng-switch.

something like

 template: '<span ng-switch on="maybeLink">' + 
          '  <span ng-switch-when="http://www.yahoo.com" ng-bind-html="text"></span>' +
          '  <a ng-switch-when="http://google.com" href="#" ng-bind-html="text"></a>' +
          '</span>',

or

 template: '<span ng-switch on="maybeLink">' + 
          '  <span ng-switch-when={{maybeLink.length == 0}} ng-bind-html="text"></span>' +
          '  <a ng-switch-when={{maybeLink.length > 0}} href="#" ng-bind-html="text"></a>' +
          '</span>',

So this is direction

Plunker