An option will be to inject the CSRF token as a constant. Append the following in your head tag:
<script>
angular.module("app").constant("CSRF_TOKEN", '{{ csrf_token() }}');
</script>
Then in your module methods it can be injected when needed.
app.factory("FooService", function($http, CSRF_TOKEN) {
console.log(CSRF_TOKEN);
};
Maybe you will be interested of peeking at the source code of this sample Laravel + AngularJS project.