One way of using Angular JS can be with IBM BPM 8.x onwards is to create a Headless UI which communicates with BPM8 using REST API calls and JSON processing, you can build a complete portal with inbox etc and also have your own user interfaces(Human Tasks) connected to input and outputs of an "external activity" in BPM, The process (BPD) manages the process flow and routing etc. but the Human tasks are built in angular js which at the beginning pick up the data from the external activity and at the end update the data and mark the task complete, similar to a Human Service, all this interaction can be done with REST API calls.