react
Metadata in NextJS drives SEO and social sharing. How to define static metadata with the metadata export, build consistent titles with templates, inherit and override values across routes, and generate dynamic metadata from fetched data.
nextjs
Layout and template in NextJS look interchangeable but behave differently: a layout preserves state across navigation while a template remounts and rebuilds it on every visit. Code examples of both, plus guidance on when each one is the right choice.
javascript
Deep equality in JavaScript is trickier than it looks: JSON.stringify fails when key order differs. Compare the real options: the deep-equal package, writing your own recursive check, lodash isEqual, and Node's built-in assert.deepStrictEqual.
BiomeJS formats and lints JavaScript, TypeScript, JSX, and JSON up to 35x faster than Prettier, with almost 97% compatibility. How to install it, migrate your Prettier config to biome.json, and cut minutes off CI without changing how your code looks.
Event bubbling in JavaScript and React: how a click travels from the target element up the DOM tree, what benefits that gives you, and why React does not really bubble events but simulates them with its synthetic event system.
What 'this' means in JavaScript: why its value depends on how a function is called, how setTimeout callbacks break your assumptions, and how bind, call, and apply put you back in control, shown with simple Dog and Cat examples.
The JavaScript event loop explained with examples: how the single-threaded call stack executes tasks, where Web APIs take over timeouts and API calls, and how the event loop decides what runs next in the non-blocking I/O model.
TypeScript's unknown vs any: both bypass strict typing, but unknown forces you to narrow a value before using it, keeping the safety any throws away. Examples show how each behaves and why unknown is the safer default for untyped data.
Sending files from JavaScript or React to a Rails API: build a FormData object with the file and extra params, POST it with fetch, then read params[:file] in your controller. A minimal frontend plus backend walkthrough that works.
JavaScript's AbortController lets you cancel fetch requests on demand: wiring an AbortSignal into fetch, calling abort, listening for the abort event, and handling cancelled requests without unhandled errors, with runnable examples.
Simplifying complicated TypeScript with the KISS principle: refactoring examples show when explicit types improve a simple function and when clever type gymnastics make code harder to review, test, and maintain.
The Record utility type in TypeScript builds object types with fixed keys and value types. A worked example shows Record<Keys, Type> with union keys: restricting IDs to chosen literals and mixing User and AdminUser values, so the compiler flags missing or extra entries.
JavaScript prototypes explained through a working example: turning a standalone myCustomForEach helper into an Array.prototype method you can call directly on any array. See how prototypes share properties and methods between instances of the same object type.
The Singleton pattern in JavaScript ensures one shared instance with a global access point. A practical implementation using an object literal and Object.freeze, a shared bucket example, and where a singleton fits: configuration, logging, or a central data store.
TypeScript function generators can pause and resume execution, returning values one at a time instead of all at once. What generators are, how yield works in a simple example, and a practical number sum generator that shows where they beat regular functions.
TypeScript types with many optional fields need comments to explain what goes together. Discriminated unions fix that: split a Task type into per-status variants so invalid combinations fail to compile and the type documents itself. Before and after code included.
Generic types in TypeScript let one function, class, or interface work safely with many data types. What generics are, how a type parameter beats hardcoding a concrete entity type in a validation helper, and honest pros and cons before you use them everywhere.
TypeScript enums generate extra JavaScript at compile time and numeric enums are not even type-safe. Why enums can hurt bundle size and correctness, and two safer alternatives: assigning explicit string values or replacing enums with plain objects.
Ruby 3.2 runs in the browser through WebAssembly: embed Ruby in a script tag with ruby-wasm-wasi or drive the Ruby VM from JavaScript and mix it with HTML. Working examples plus honest limits: no threading or networking, and no extra gems without a custom wasm image.
Map vs WeakMap in JavaScript comes down to keys and memory: WeakMap only accepts object keys and lets garbage collection reclaim unused entries, while Map holds onto everything. Differences, similarities, and practical guidance on when each one is the right choice.