list of programming languages
A loop is a sequence of instructions. A functional iteration is a transformation of a collection. The difference is not just style; it is what the code expresses. A for loop says “do this to each element.” A map says “this collection becomes that collection.” The functional operations—map, where, fold, reduce, expand—are the methods on…
Polymorphism means “many forms” — it’s the ability of different classes to respond to the same method call in their own way. It’s one of the four pillars of object-oriented programming (along with encapsulation, inheritance, and abstraction). A Quick Look at the Example Key idea: animal.speak() looks identical for every animal, but produces a different…
Fastify is a web framework for Node.js that was engineered around a single principle: add as little overhead as possible on top of the runtime. Where Express builds its abstraction from a middleware chain that grows with every plugin, Fastify builds a graph of encapsulated plugins, each with its own scope, and it compiles the…
The Result<T, E> carries an error type. The error type can be a String, a library error like io::Error, or a custom type the application defines. A custom error type is the tool for the applications that have their own failure modes: a validation failure, a configuration failure, a domain-specific failure that the standard library…
The LEFT JOIN returns all rows from the left table and the matching rows from the right table. When a left row has no match in the right table, the right table’s columns are filled with NULL, and the row still appears in the result. This is the behavior that distinguishes an outer join from…
Chapter 34 covered the object-shape utilities: Partial, Required, Readonly, Pick, Omit. This chapter covers the union utilities and the one object-construction utility: Record<K, V> builds an object type from a key type and a value type, Exclude<T, U> removes union members assignable to U, Extract<T, U> keeps only the members assignable to U, and NonNullable<T>…
These two media features are the cornerstones of responsive design. They let you apply styles based on the viewport’s dimensions, enabling layouts that adapt to any screen size. Overview of Features Feature Description Values height Viewport height Exact, min-height, max-height width Viewport width Exact, min-width, max-width 1. height The height media feature applies styles based…
Dart programs run on a single thread. Every line of synchronous code executes in order, one after another, on that one thread. This is simple, predictable, and fast — until the code needs to wait. A network request takes hundreds of milliseconds. A file read takes milliseconds to seconds. A timer takes however long it…
The Iterator interface defines a standard way to access elements of a collection one at a time. It’s the mechanism that powers for…of loops, spread syntax, and destructuring in JavaScript. A Quick Look at the Example Key idea: An iterator is an object with a next() method that returns { value, done } on each…
Fastify is built on a single architectural bet: encapsulation. Every call to register() creates a new child context, and anything a plugin adds to itself — routes, decorators, hooks — is visible to that plugin’s descendants but invisible to its siblings and ancestors . This is not a minor implementation detail. It is the mechanism…