silphius/app/packets/index.js

import gather from '@/util/gather.js';

const Gathered = gather(import.meta.glob('./*.js', {eager: true, import: 'default'}));

const typeToId = new Map(Object.entries(Gathered).map(([type], id) => [type, id]));
const idToType = new Map(Object.entries(Gathered).map(([type], id) => [id, type]));

export function decode(packed) {
  const view = ArrayBuffer.isView(packed) ? packed : new DataView(packed);
  const type = idToType.get(view.getUint16(0, true));
  const Packet = Gathered[type];
  return {
    type,
    payload: Packet.decode(view),
  };
}

export function encode(packet) {
  const encoded = Gathered[packet.type].encode(packet.payload);
  encoded.setUint16(0, typeToId.get(packet.type), true);
  return encoded;
}