SprigJS Documentation

Specifications and Limits ​

This page reflects the framework's current specification and implementation status. Recommended targets that are not implemented or verified are not release promises.

Implemented ​

  • Fine-grained signals, computed getters, synchronous effects, cleanup roots, and reactive proxies for plain objects and arrays.
  • Direct DOM helpers, reactive children and properties, native event cleanup, component mounting/disposal, and keyed list reconciliation.
  • Vite compilation of .sprig single-file components with the documented template subset, global/scoped styles, slots, and component imports.
  • Optional sprig-framework/router add-on with hash routing, opt-in History API routing, parameterized file routes, nested layouts, and lazy route loading; the core also provides a load-on-visible helper.
  • An optional sprig-framework/form add-on for form values, validation, touched state, async submission, and reset.
  • An optional sprig-framework/dialog add-on for a message dialog with Cancel/OK results and Sprig-owner cleanup.
  • An optional sprig-framework/dialog add-on for a message dialog with Cancel/OK results and Sprig-owner cleanup.
  • An optional sprig-framework/animation add-on for Web Animations API playback, explicit transitions, opt-in page/@if/@for lifecycle transitions, Sprig owner cleanup, and reduced-motion handling.
  • Optional TypeScript declarations for the public API; TypeScript is not required to use the JavaScript runtime.

Current boundaries ​

  • The .sprig Vite plugin is an internal repository source module, not a package export. See Getting Started for the repository build and integration setup.
  • Sprig is browser-oriented and client-rendered. Server-side rendering and hydration are not implemented.
  • The template compiler supports a focused subset and JavaScript-only <script setup> blocks. It is not a full Vue/Svelte compiler; JSX, arbitrary two-way binding expressions, automatic transitions without importing/enabling the add-on, and accessibility automation are not provided. See the animation add-on for opt-in lifecycle transitions.
  • File-route parameters match one segment. Catch-all file routes are not supported.
  • History-mode deployments need a server-side index.html fallback for direct visits and refreshes.
  • There is no built-in HTTP wrapper. Use the browser's fetch() or another application-level choice.
  • The example Python http.server API is local-only and has no authentication or per-user authorization. It must not be exposed publicly.
  • Tree-shaking is verified for the public entries with Vite production-consumer tests; other bundlers/configurations are not exhaustively verified. Runtime-size and broader code-splitting recommendations remain targets.

For the detailed source specification, see the repository's SPECS.md.