- Python – Dictionaries & Sets
The dict, which is the data structure Python is built on, and the set, which answers membership and de-duplication in one line. get and setdefault, iteration, dict and set comprehensions, and what makes a key hashable.
- Java 11 New File and Collection Methods
Beyond the String methods , Java 11 added a handful of small API improvements. Each one removes a few lines you used to write by hand, and two of them — Files.readString and Path.of — you will use constantly. Reading and writing a whole file Both default to UTF-8, which is the important detail. The…
- React – Custom Hooks
A custom hook is a function whose name starts with use and that calls other hooks. That is the entire specification. Extracting stateful logic so two components can share it, why hooks share logic and never state, the one-line hook that turns a context into a typed API and throws when used outside its provider.
- Angular – HTTP Interceptors
One place to attach the auth token, and one place to catch a 401. Functional interceptors and how they chain, adding an `Authorization` header, translating server errors into something the UI can show, a loading indicator driven by in-flight requests, and why interceptor order is not an implementation detail.
- Docker – Environment Variables, Build Args and Secrets
One image, many environments — the whole point of configuring from outside. `ENV` versus `ARG` and why a build arg is baked into the image forever, `--env-file`, Spring Boot's relaxed binding turning `SPRING_DATASOURCE_URL` into a property, frontend config that is baked at build time, and where secrets actually go.