Webhook

Styled Components is a popular CSS-in-JS library for React and React Native that uses tagged template literals to style components. It automatically generates unique class names, supports dynamic styling based on props, handles vendor prefixing, and provides full theming capabilities. The library colocates styles with components, making it easy to understand what each component looks like and to delete styles safely when removing components.

Shadow DOM is a browser API that allows you to attach a hidden, encapsulated DOM tree to an element, isolating its styles and markup from the rest of the page. This means CSS defined inside a Shadow DOM won't leak out, and external styles won't bleed in. It's the core technology behind Web Components and is used by frameworks to achieve true style encapsulation without CSS naming conventions or tooling.

Code splitting is an optimization technique that breaks a JavaScript bundle into smaller chunks that are loaded on demand, rather than forcing users to download the entire application upfront. In React, this is achieved through `React.lazy()` and dynamic `import()` statements, which create separate bundles loaded only when the corresponding component or route is accessed. This dramatically improves initial load times, especially for large single-page applications with many routes.

Container Queries allow CSS styles to respond to the size of a parent container rather than the browser viewport, solving a long-standing limitation of media queries. By marking an element as a containment context with `container-type`, its children can use `@container` rules to adapt their layout based on the container's dimensions. This makes truly reusable components possible — a card component can rearrange itself whether it's in a sidebar or a full-width section.

Memoization in React is a performance optimization that caches the result of expensive computations or component renders to avoid redundant work on re-renders. React provides `React.memo()` to skip re-rendering a component when its props haven't changed, `useMemo()` to cache computed values, and `useCallback()` to cache function references. While powerful, premature memoization adds complexity — it's best applied after profiling confirms an actual performance bottleneck.

A cron job is a time-based task scheduler originating from Unix systems that runs commands or scripts at specified intervals. The schedule is defined using a cron expression with five fields representing minute, hour, day, month, and weekday. Cron jobs are fundamental for automations like database backups, log rotation, report generation, and periodic data synchronization.