Swamy It doesn't say it only supports PHP, it says it requires PHP to run, which is true.
Now, you can integrate it with infinitely anything else if you code it right, using the REST API as @Mekers mentioned.
You could look at Single Sign On to get an idea of how to implement this.
Now, when you mention NodeJS, are you referring to the backend of the application being in NodeJS, or you needing NodeJS & NPM to build the Angular application?
