list of programming languages
A WebSocket connection begins as an HTTP request. The client sends an Upgrade header, the server responds with 101 Switching Protocols, and the TCP socket transitions from request-response to full-duplex messaging. The ws library implements this handshake and the framing that follows. It is the most widely deployed WebSocket library in the Node.js ecosystem, with…
Rust’s ownership rules guarantee that a value is dropped when its owner goes out of scope. The guarantee holds for trees, stacks, and every structure where ownership is acyclic. It breaks for cycles. When two Rc<T> values point to each other, each keeps the other’s strong count above zero, and neither is dropped. The memory…
The window functions so far access the adjacent rows and the ranked positions. The boundary functions—FIRST_VALUE, LAST_VALUE, and NTH_VALUE—access the specific rows at the edges of the window or at the arbitrary position. They answer the questions “what was the first value?” and “what was the last value?” and “what was the third value?” The…
A .d.ts file is a declaration file — a TypeScript file that contains only type information, no runtime code. It describes the shape of something that exists at runtime: a JavaScript library, a global variable, a module that is written in another language, a build artifact. The compiler reads the file for types and emits…
Dart’s web platform is unique in that it compiles to two different targets: JavaScript for the traditional browser runtime, and WebAssembly for the modern, high-performance runtime. For years, these two targets had separate interop mechanisms, and code that worked on one did not work on the other. The dart:js_interop library unifies them. It provides a…
Class fields are the modern way to declare properties on a class. They replace constructor assignments, give you true private fields with #, and provide static members for class-level data. Combined with static initialization blocks, they make class definitions cleaner and more powerful. Key point: Class fields are per-instance by default. #private fields are truly…
A raw WebSocket connection carries frames. It does not carry meaning. The application must define the message types, the routing, the rooms, the acknowledgments, and the fallbacks. Socket.IO is the layer that provides all of these. It builds on the WebSocket protocol, adds a fallback to HTTP long-polling when WebSockets are not available, and exposes…
The Rc<T> smart pointer provides shared ownership on a single thread, but the reference count is a plain integer. Incrementing it from two threads is a data race, and the compiler rejects sending an Rc across a thread boundary. The Arc<T> type — “atomic reference counted” — is the thread-safe counterpart. It uses an AtomicUsize…
The aggregate functions—SUM, AVG, MIN, MAX, COUNT—have two lives in SQL. The first is the GROUP BY form: the rows are collapsed, and one row per group is returned. The second is the window form: the OVER clause keeps all the rows, and the aggregate is attached to each one. This chapter is about the…
An ambient declaration is a description of something that exists at runtime but has no implementation in the current compilation. The word “ambient” means the declaration is a claim, not a definition. When TypeScript sees declare const VERSION: string, it accepts that a VERSION variable exists and trusts that the runtime provides it. The declaration…