- TypeScript – Arrays and Tuples
string[] versus Array<string>, arrays of unions versus unions of arrays, and readonly arrays that stop a helper mutating its argument. Then tuples: fixed length, typed per position, and the one in this app's date formatter that would be Array<string | number> without them — which is to say, useless.
- NestJS – Controllers
Routing, and the line between HTTP and everything else. Route decorators, @Body, @Param and @Query, why POST answers 201 by default and when that is wrong, choosing 204 over an empty 200, and the rule that keeps controllers thin — a controller that decides who may do something is in the wrong layer.
- 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…
- 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.