- TypeScript – The Basic Types
string, number, boolean and the annotations you do not need to write. Where inference is better than an explicit type and where it quietly gives up, why let and const infer differently, literal types, and the one place a return type is worth writing by hand even though TypeScript could work it out.
- NestJS – Setting Up a Project
Creating a project with the Nest CLI, what each generated file is for, and the tsconfig flags Nest actually needs — experimentalDecorators and emitDecoratorMetadata are not style settings, they are what makes injection work. Plus the ESM trap that costs everyone an afternoon: why every relative import in this codebase ends in .js even though the file is .ts.
- Python – Iteration (for / while loops)
The for loop that walks a sequence rather than an index, when a while loop is the right shape, range, enumerate and zip, break and continue, and the loop-else clause almost nobody knows is there.
- Interface default methods and static methods
Before Java 8, adding a method to an interface broke every class that implemented it. That is not a theoretical problem — it is why Collection went years without obvious conveniences. Default methods solved it, and understanding why they exist tells you when to use them. The problem they were…
- React – Passing Data Deeply with Context
Prop drilling is passing a value through five components that do not use it. Context is the way out: createContext, a provider component that owns the state, useContext to read it anywhere below. What belongs in context and what does not, why every consumer re-renders when the value changes, and how to keep that from hurting.