Is it possible to make a Tree View with Angular?

Question

Have a look at this fiddle

Original: http://jsfiddle.net/brendanowen/uXbn6/8/

Updated: http://jsfiddle.net/animaxf/uXbn6/4779/

This should give you a good idea of how to display a tree like structure using angular. It is kind of using recursion in html!

If you are using Bootstrap CSS...

I have created a simple re-usable tree control (directive) for AngularJS based on a Bootstrap "nav" list. I added extra indentation, icons, and animation. HTML attributes are used for configuration.

It does not use recursion.

I called it angular-bootstrap-nav-tree ( catchy name, don't you think? )

There is an example here, and the source is here.

When making something like this the best solution is an recursive directive. However, when you make such an directive you find out that AngularJS gets into an endless loop.

The solution for this is to let the directive remove the element during the compile event, and manually compile and add them in the link events.

I found out about this in this thread, and abstracted this functionality into a service.

module.factory('RecursionHelper', ['$compile', function($compile){
    return {
        /**
         * Manually compiles the element, fixing the recursion loop.
         * @param element
         * @param [link] A post-link function, or an object with function(s) registered via pre and post properties.
         * @returns An object containing the linking functions.
         */
        compile: function(element, link){
            // Normalize the link parameter
            if(angular.isFunction(link)){
                link = { post: link };
            }

            // Break the recursion loop by removing the contents
            var contents = element.contents().remove();
            var compiledContents;
            return {
                pre: (link && link.pre) ? link.pre : null,
                /**
                 * Compiles and re-adds the contents
                 */
                post: function(scope, element){
                    // Compile the contents
                    if(!compiledContents){
                        compiledContents = $compile(contents);
                    }
                    // Re-add the compiled contents to the element
                    compiledContents(scope, function(clone){
                        element.append(clone);
                    });

                    // Call the post-linking function, if any
                    if(link && link.post){
                        link.post.apply(null, arguments);
                    }
                }
            };
        }
    };
}]);

With this service you can easily make a tree directive (or other recursive directives). Here is an example of an tree directive:

module.directive("tree", function(RecursionHelper) {
    return {
        restrict: "E",
        scope: {family: '='},
        template: 
            '<p>{{ family.name }}</p>'+
            '<ul>' + 
                '<li ng-repeat="child in family.children">' + 
                    '<tree family="child"></tree>' +
                '</li>' +
            '</ul>',
        compile: function(element) {
            return RecursionHelper.compile(element);
        }
    };
});

See this Plunker for a demo. I like this solution best because:

1. You don't need an special directive which makes your html less clean.
2. The recursion logic is abstracted away into the RecursionHelper service, so you keep your directives clean.

Update: Added support for a custom linking functions.

angular-ui-tree seems to do a good job for me

Here is an example using a recursive directive: http://jsfiddle.net/n8dPm/ Taken from https://groups.google.com/forum/#!topic/angular/vswXTes_FtM

module.directive("tree", function($compile) {
return {
    restrict: "E",
    scope: {family: '='},
    template: 
        '<p>{{ family.name }}</p>'+
        '<ul>' + 
            '<li ng-repeat="child in family.children">' + 
                '<tree family="child"></tree>' +
            '</li>' +
        '</ul>',
    compile: function(tElement, tAttr) {
        var contents = tElement.contents().remove();
        var compiledContents;
        return function(scope, iElement, iAttr) {
            if(!compiledContents) {
                compiledContents = $compile(contents);
            }
            compiledContents(scope, function(clone, scope) {
                     iElement.append(clone); 
            });
        };
    }
};
});