list of programming languages
Dart’s Stream is the language’s native abstraction for asynchronous sequences of data. A StreamController is the object that creates and manages a stream, allowing you to add events that listeners receive asynchronously. This is a complete and capable mechanism on its own. But it has a specific limitation that becomes apparent the moment you try…
Large numbers are hard to read. 1000000000 and 100000000 look almost identical at a glance — one is a billion, the other is a hundred million, and the human eye can’t reliably tell them apart. Numeric separators fix this: an underscore you place wherever you want, that JavaScript ignores entirely. The feature is small. It…
The node:test module includes a mocking system built into the runtime. It provides spies, stubs, method replacement, and fake timers without requiring Sinon, Jest, or any other third-party library. The mocking API is exposed through the mock object and through the TestContext object that every test function receives. The distinction between these two entry points…
Rust does not allow you to invent new operators or overload arbitrary syntax. What it allows is a carefully bounded form of operator overloading: certain operators are tied to specific traits in std::ops, and implementing those traits for your type defines what the operator means for that type . The + operator is syntactic sugar…
A database serves many clients at once. Two customers buy the last item in stock. A report runs while an order is being processed. An analyst sums account balances while a transfer moves money between them. These concurrent operations are the normal state of any production database, and without careful control they produce results that…
Strict mode is not a single setting. It is a group of compiler options that tighten TypeScript’s type checking, and each one catches a different class of bug. The strict: true flag enables the core set, but several important options sit outside it. Knowing what each flag does, and what it costs, is the difference…
Dart’s type system is null-safe, but null safety only catches the absence of a value when the compiler can prove it. It does not prevent a function from throwing an exception, nor does it make the failure path visible in the type signature. A method that returns User might throw a NetworkException or a FormatException,…
Before ES2022, await only worked inside async functions. To use it at the module’s top level, you had to wrap everything in an async IIFE — a workaround that added noise to every file that needed to fetch config, load a database connection, or initialize resources before exporting anything. Top-level await changes that. In an…
Jest and Vitest both provide the same core testing vocabulary—describe, it, expect, mocks, snapshots, and coverage—but they are built on fundamentally different foundations. Jest was created in the CommonJS era and has spent years retrofitting support for ES modules and TypeScript through Babel transforms and experimental flags . Vitest was built from the start on…
Rust’s type system requires that every value have a size known at compile time. This is not an arbitrary restriction—it is what allows the compiler to allocate stack space, pass arguments by value, and lay out struct fields. The Sized marker trait is how the compiler encodes this requirement . Every type parameter in a…