posy-protocol (reference JS/TS)

TypeScript reference encoder/decoder for the Posy pose protocol. Zero runtime dependencies, Node ≥ 18. Published on npm as posy-protocol.

npm install posy-protocol

import { encode, decode, VERSION } from 'posy-protocol';

const bytes = encode({
  version: VERSION, seq: 1, timestampMs: 0, // the minor revision this release writes (spec §9)
  bones: new Map([[0, { x: 0, y: 0, z: 0, w: 1 }]]), // hips, identity
});
const frame = decode(bytes); // throws on any malformed frame

// A sender with declared extras (spec §2.6): the block size is not in the frame.
// Pass the list lengths of the declaration that applies at timestampOf(bytes).
const withExtras = decode(bytes, { bones: 4, values: 3 });

Build and test:

npm ci && npm test   # builds, then runs the unit tests + test vectors

The spec is the source of truth: if this code ever disagrees with spec/Posy.md, the spec wins and the code gets fixed.