Check if a REST response with an array contains a specific value

Summary

Access to application level variables and looping through arrays.

Content

We have a set of REST API's for our application data.
We also have custom roles defined in our application and at some pont, these are fetched from the database via a REST call.
The returning user info includes the roles and has the following format:

{
    "status"       : "Login succesfull",
    "user"         : "rob.de.gouw@darwin-it.nl",
    "client_id"    : "MyId",
    "client_secret": "MySecret",
    "name"         : "Rob de Gouw",
    "roles"        : [
        {
            "name"  : "Employee",
            "active": "J"
        },
        {
            "name"  : "Manager",
            "active": "J"
        }
    ]
}

This response is mapped to an application level variable

We would like to make certain areas of the application inaccessible for employees who are not manager.