$ show transloadit/uppy
Uppy is a modular, client-side JavaScript file upload library with a companion server (Companion) for remote provider integrations. It provides a plugin-based architecture where core functionality (file selection, upload strategies, UI components) is encapsulated in reusable packages. The client-side library supports drag-and-drop, webcam/screen capture, image editing, thumbnail generation, and multiple upload backends (tus resumable, AWS S3 multipart, XHR, Transloadit). The Companion server handles OAuth flows, remote file listing/download from providers like Google Drive, Dropbox, Box, OneDrive, Facebook, Zoom, Unsplash, and WebDAV, as well as S3 presigning and Transloadit Storage integration. The repository is a monorepo with over 50 packages, including framework-specific wrappers for React, Vue, Svelte, and Angular, plus headless controllers for custom UI. Key entry points are @uppy/core (Uppy class, plugin system), @uppy/dashboard (main UI), @uppy/companion (Express server), and @uppy/aws-s3 (S3 upload client). Data flows: user selects files via UI plugins, which are then uploaded via configured uploader plugins; remote sources are fetched through Companion using OAuth tokens. External dependencies include tus-js-client, AWS SDK, Transloadit API, and various OAuth providers. The codebase is well-tested with unit, integration, and browser tests, and uses modern TypeScript, ESM, and Preact for UI.
The LLM identified 5 files worth highlighting for reuse:
A reusable concurrency utility that manages a queue of tasks with configurable concurrency limit, priority, pause/resume, and automatic rate limiting on 429 responses. It supports wrapping promise functions and provides a `wrapPromiseFunction` for legacy compatibility. This is a self-contained pattern that can be extracted for any project needing controlled parallel execution with backpressure.
A lightweight internationalization utility that supports string interpolation and pluralization with custom pluralization functions. It is framework-agnostic and can be used in any JavaScript project. The implementation is clean, well-tested, and demonstrates a non-obvious approach to handling plural forms without a heavy library.
A set of pure functions for managing a partial tree data structure used for browsing remote file providers. Includes operations like afterFill (load children), afterToggleCheckbox (recursive selection), getBreadcrumbs, getCheckedFilesWithPaths, and shallowClone. These functions are self-contained, well-typed, and can be reused in any tree-based file browser UI.
A standalone implementation of AWS Signature V4 presigning for S3 requests, supporting both simple and multipart uploads. It handles key derivation, canonical request construction, and query parameter signing. This is a non-trivial cryptographic utility that can be extracted and used in any browser or Node.js project needing direct S3 presigned URLs without the full AWS SDK.
A framework-agnostic controller for webcam capture that exposes state via subscribe/getSnapshot (compatible with React's useSyncExternalStore). It manages camera stream, recording, snapshot, and permissions. The pattern is reusable for any media capture UI and demonstrates clean separation of concerns between state logic and rendering.