As a consultant at Capgemini-Sogeti High Tech I built the web interfaces for EATON’s Intelligent Power Manager — real-time energy dashboards for UPS-backed data centres and facilities, including Eaton’s own site at Grenoble-Montbonnot.
The interface shows live consumption and lets an operator descend through it, from a facility down to an individual device. That hierarchy is the feature. A site-level number tells you something is wrong; the drill-down is how you find which rack.
Readings arrive continuously from many devices and several views show overlapping slices of the same data. If each component holds its own subscription you get views that disagree with each other, and nothing on screen signals that it has happened, which for monitoring software is the failure you least want. So the readings live in NgRx as one store, with RxJS composing the derived streams each view needs and ImmutableJS and Immer keeping updates from mutating state in place. Components select from the store instead of owning state, so two views of the same device read the same value.
I also coordinated work packages across the back-end and firmware teams. What the interface can show is bounded by what the hardware reports and how often, so the front end could not be specified on its own.