Define rootscope variable in an .ASPX file

I am trying to define an AngularJS rootscope variable in a .ASPX file to use in a TypeScript file, but I am unsure of how to do this. I am open to any way to be able to define a value in an .ASPX file and use it in TypeScript, so any other suggestion will work for me.

If you simply need to tell TypeScript that the property is there, you can extend the rootScope interface:

interface extendedRootScope extends ng.IRootScopeService {
    myProp: number;
}

Then when you inject $rootScope in your controller, type it as your new interface:

export class MyController {
    constructor(private $rootScope: extendedRootScope) { }

    someMethod() {
        // Access this.$rootScope.myProp
    }
}

If you need to access $rootScope from outside the Angular world (like in your ASPX page) to add the property, you can do something like this:

<script>
    var injector = angular.element('[ng-app]').injector();
    var $rootScope = injector.get('$rootScope');

    $rootScope.myProp = 1;
</script>

This assumes you are using ng-app to initialize your Angular app.

Similarly, you could create an Angular service on the fly in a script tag, inject $rootScope into that service, and add properties to it.