Dictionary

A context window is the maximum amount of text (measured in tokens) that an LLM can process in a single interaction, encompassing both the input prompt and the generated output. Larger context windows allow models to handle longer documents, maintain extended conversations, and reason over more information at once. Context window sizes have grown rapidly — from 4K tokens in early GPT models to over 1M tokens in current models like Claude.

A controlled component is a form element in React whose value is driven by React state rather than the DOM's own internal state. The component's value is set through a `value` prop and updated via an `onChange` handler, giving React full control over the form data. This pattern enables validation on every keystroke, conditional disabling of submit buttons, and enforcing input formats, making it the recommended approach for most form handling in React applications.

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.

Cross-platform development is the practice of building applications that run on multiple operating systems (iOS, Android, web, desktop) from a single codebase. Frameworks like React Native, Flutter, and Kotlin Multiplatform each take different approaches — from shared UI rendering to shared business logic with native UI. The key trade-off is between code reuse efficiency and the ability to deliver platform-native experiences that feel right on each device.

Dark mode is a UI color scheme that uses light-colored text and elements on a dark background. It reduces eye strain in low-light environments, can save battery on OLED screens, and has become an expected feature in modern applications. Implementation typically involves CSS custom properties or design tokens that switch between light and dark theme values, often respecting the user's system-level preference via the `prefers-color-scheme` media query.

Dart is the programming language created by Google and used as the sole language for Flutter development. It features a sound type system, null safety, async/await support, and compiles both ahead-of-time (AOT) for production performance and just-in-time (JIT) for fast development cycles with hot reload. Dart's syntax feels familiar to developers coming from JavaScript, TypeScript, Java, or Kotlin, making the transition to Flutter relatively smooth.

Deep linking is the ability to direct users to a specific screen or content within a mobile or web application via a URL, rather than just opening the app's home screen. In React Native and Flutter, this involves configuring URL schemes (e.g., `myapp://profile/123`) or universal/app links that work across platforms. Deep linking is essential for push notification routing, marketing campaigns, sharing content between users, and creating seamless web-to-app transitions.

A design system is a collection of reusable components, guidelines, and standards that ensure visual and functional consistency across a product or suite of products. It typically includes a component library, design tokens, typography rules, color palettes, and documentation. Design systems bridge the gap between designers and developers, enabling teams to build interfaces faster while maintaining a unified look and feel.

Design tokens are the smallest units of a design system — named values representing colors, spacing, typography, border radii, and other visual properties. They act as a single source of truth that can be translated into platform-specific formats (CSS variables, Swift constants, XML resources). By changing token values in one place, you can update the look and feel of an entire application across multiple platforms simultaneously.

A diffusion model is a type of generative AI that creates data by learning to reverse a gradual noise-adding process. During training, the model learns to progressively denoise random noise into coherent outputs like images, audio, or video. Diffusion models power tools like Stable Diffusion, DALL-E, and Midjourney, and have become the dominant architecture for high-quality image generation.

Docker is a platform that packages applications and their dependencies into lightweight, portable containers that run consistently across any environment. A Dockerfile defines the build steps, and images can be shared via registries like Docker Hub. Containers are essential for automation because they guarantee that code behaves the same in CI pipelines, staging, and production, eliminating "works on my machine" issues.

Drag and drop is an interaction pattern that lets users move, reorder, or transfer UI elements by clicking (or touching), holding, and dragging them to a new position. It's used for file uploads, kanban boards, sortable lists, and layout builders. The HTML Drag and Drop API provides native browser support, while libraries like dnd-kit and react-beautiful-dnd offer more polished, accessible, and touch-friendly implementations.