Plunker: http://plnkr.co/edit/wmf4t70Di19Vtk89TWgK?p=preview
This is a directive that uses google-diff-match-patch to show the semantic diff between two HTML strings, while preserving the HTML formatting. The point is to show the diff of two sets of "rich text" that has typically been entered by a user into a rich text input such as textAngular.
The idea for this approach came from a stackoverflow answer. I couldn't find an actual implementation anywhere, so I created one.
You will need to include angular-sanitize.js in your project, as this directive depends on ngSanitize in order to display the resulting HTML.
This dependency is declared in the bower.json, but you will still need to be sure to include the google-diff-match-patch.js file in your project.
Install from bower:
bower install angular-rich-text-diff
Include angular-rich-text-diff.js and google-diff-match-patch.js in your index.html. Add the module to your app's dependencies:
angular.module('app', ['angular-rich-text-diff']);
Put the following HTML somewhere, where left and right are strings containing the before and after HTML you want to diff:
<rich-text-diff left="beforeString" right="afterString"></rich-text-diff>
The CSS in angular-rich-text-diff.css will highlight additions in green and deletions in red.