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JavaScript

JavaScript binding

Status​

Planned. Development will begin after the Python binding stabilizes.

Timeline​

The JavaScript binding is expected to follow the core systems-language bindings (Rust, JVM, .NET, Go) in priority.

Architecture​

Two approaches are under consideration:

Option A: WASM​

Compile the core crate to WebAssembly for use in browsers and edge runtimes (Deno, Cloudflare Workers).

JavaScript / TypeScript application code
        |
        v
@aster/client npm package     Idiomatic JS API: decorators (TC39),
                              AsyncIterator for streaming, AbortSignal for cancellation
        |
        | wasm-bindgen
        v
core.wasm                     Core crate compiled to WASM
        |
        v
iroh crates (WASM-compatible subset)

WASM provides the broadest reach (browsers, edge, Node.js) but may have limitations around direct UDP access. Browser-based consumers would connect via WebSocket-to-QUIC relay bridges.

Option B: N-API (Node.js native addon)​

Use N-API to expose the core crate as a native Node.js addon, similar to the Python PyO3 approach.

JavaScript / TypeScript application code (Node.js)
        |
        v
@aster/client npm package     Idiomatic JS API
        |
        | N-API
        v
aster.node                    Native addon built from core crate
        |
        v
iroh crates (full functionality)

N-API provides full access to the networking stack (including direct UDP) but is limited to Node.js and compatible runtimes.

Key design decisions​

  • TypeScript-first with full type definitions.
  • TC39 decorators (Stage 3) for service definitions where available; plain class registration as a fallback.
  • AsyncIterator for streaming patterns.
  • AbortSignal for cancellation and deadline propagation.
  • Apache Fory JavaScript will handle XLANG serialization for wire compatibility.

Requirements​

  • Node.js 18+ (for N-API) or any modern browser/edge runtime (for WASM).
  • The native addon or WASM module for the target platform.

Further reading​