Most Angular developers learn Observable syntax but never make the mental shift to stream thinking. This article shows the step-by-step transformation from basic API calls to enterprise-grade data pipelines. I walk through 5 real production problems (slow networks, failed requests, memory leaks, etc.) and show how each Observable operator solves a specific issue. The goal is changing how you think about data flow, not just memorizing RxJS operators.
Fair point on the title. The core principle is universal: only send necessary data to clients. I focused on Angular because the pipe + service patterns make this mistake particularly common. Tutorials teach client-side filtering with pipes, and services naturally cache complete datasets for "performance." I've seen this exact vulnerability in multiple Angular codebases following "best practices."The underlying issue applies to any framework, but Angular's conventions seem to make it easier to stumble into this anti-pattern.
