SAPUI5 - Accessing current sub-account from the controller.

I'm accessing a URI from my controller which at the moment is hardcoded to my current SAP Cloud Platform Sub-Account.

window.open("https://rsaactionplan-%28subaccount%29.dispatcher.hana.ondemand.com/index.html#/actionplan/">rsaactionplan-(subaccount).dispatcher.hana.ondemand.com/index.html#/actionplan/" + oBindingContext.JobId, "_system");

Rather than hard-code it, how can I access the current sub-account ID so I can dynamically setup the sub-account in the SAPUI5 controller?