Html file as content in Bootstrap popover in AngularJS directive

Question

I have an Angular directive to handle Bootstrap popovers as shown in the code below. In my directive I'm setting the popover content to a HTML string, which I think is ugly. What I wanna do is to use an "template.html" file instead of HTMLstring. In that way I will be able to use the same directive with different template files depending on which type of popover I wanna show. That's my plan anyway.

So, how do I in the best way load html code from my template.html and use it instead of the HTMLstring in the AngularJs directive below?

app.directive('mypopover', function ($compile) {

var HTMLstring = "<div><label class='control-label' style='color: rgb(153, 153,153)'>Search</label>&nbsp;&nbsp;"+"<input placeholder='Search assignment' ng-model='searchText' type='text' class='form-control'> <br>"+"<label class='control-label' style='color: rgb(153, 153, 153)'>Select an assignable</label>"+"<p ng-repeat='p in projects | filter:searchText'ng-click='createEvent(user.id,date)'>"+"{{p.title}}</p></div>";

var getTemplate = function (contentType) {
    var template = '';
    switch (contentType) {
        case 'user':
            template = HTMLstring;
            break;
    }
    return template;
}
return {
    restrict: "A",
    link: function (scope, element, attrs) {
        var popOverContent;
        if (scope.user) {
            var html = getTemplate("user");
            popOverContent = $compile(html)(scope);                    
        }
        var options = {
            content: popOverContent,
            placement: "right",
            html: true,
            date: scope.date
        };
        $(element).popover(options);
    },
    scope: {
        user: '=',
        date: '='
    }
};
});

Answer 1

A quick solution is using templateCache with inline template:

Inline template:

<script type="text/ng-template" id="templateId.html">
      This is the content of the template
</script>

Js:

app.directive('mypopover', function ($compile,$templateCache) {

    var getTemplate = function (contentType) {
        var template = '';
        switch (contentType) {
            case 'user':
                template = $templateCache.get("templateId.html");
                break;
        }
        return template;
    }

DEMO

If you need to load external templates, you need to use ajax $http to load the templates manually and put in the cache. Then you can use $templateCache.get to retrieve later.

$templateCache.put('templateId.html', YouContentLoadedUsingHttp);

Sample code:

var getTemplate = function(contentType) {
    var def = $q.defer();

    var template = '';
    switch (contentType) {
      case 'user':
        template = $templateCache.get("templateId.html");
        if (typeof template === "undefined") {
          $http.get("templateId.html")
            .success(function(data) {
              $templateCache.put("templateId.html", data);
              def.resolve(data);
            });
        } else {
           def.resolve(template);
        }
        break;
    }
    return def.promise;
  }

DEMO

Answer 2

To complete the answer from Khahn, if you load a dynamic template, the last part should look like that:

return {
restrict: "A",
scope: {
    item: "=" // what needs to be passed to the template
},
link: function(scope, element, attrs) {

  getTemplate("user").then(function(popOverContent) {

    var options = {
      content: $compile($(popOverContent))(scope),
      placement: "bottom",
      html: true,
      trigger: "hover"
    };
    $(element).popover(options);

  });
}

};