A standalone hub in Node

A hub on the mesh is three things: an address deliveries route to, message handlers keyed by message type (the C# WithHandler<T>), and state the handlers own. None of that is .NET-specific. This page programs a hub in Node/TypeScript, connects it to the mesh over gRPC, and serves it — the Node counterpart of A standalone hub in Python.

The working code is clients/typescript/src/examples/hub.ts; the SDK is @meshweaver/client (clients/typescript).

Define the hub

Hub is the model — an address, handlers by message type, owned state. A raising handler answers with an ErrorResponse instead of wedging; the reply is correlated back to the sender automatically.

import { connect, Hub } from "@meshweaver/client";

const conn = await connect("https://memex.meshweaver.cloud", { token: "mw_…", address: "node/counter" });

let count = 0;                                              // the state the handlers own
new Hub(conn)
  .register("Increment", (d) => { count += Number(d.message.by ?? 1); return ["Count", { value: count }]; })
  .register("GetCount", () => ["Count", { value: count }]);

Any participant now drives it over the mesh: observe("node/counter", "Increment", { by: 5 }) returns { value: 5 }. The hub reads the mesh (mesh.get / mesh.search / mesh.watch) and writes back (mesh.patch / mesh.create) exactly like a C# hub — see Foreign Language Integration.

Run it as the node kernel

The same SDK ships the node kernel — a specialised hub at node/node-kernel that executes javascript/typescript Code nodes routed to it (CodeNodeType.ResolveKernelAddress). It runs the snippet in a vm sandbox with REPL semantics (console.log captured, a trailing expression is the return value, Inputs exposes caller parameters; TypeScript is transpiled first) and patches the run's Activity node — so js/ts output surfaces identically to python and C#.

cd clients/typescript
npm install && npm run build
node dist/worker.js --url https://memex.meshweaver.cloud --token mw_… --address node/node-kernel
node dist/worker.js --demo     # self-contained smoke test: execute a JS + a TS snippet

In a deployment it ships as a trusted sidecar in the portal pod (the Node gate, deploy/node-gate), connecting to the trusted loopback endpoint with no token — reachability is the authentication. It is feature-flagged alongside the python gate under grpc.gates (every language included by default). Full model: Python Code Nodes.

A standalone hub in Python — the same hub model in Python.
Python Code Nodes — how a Code node routes to a language worker and back.
Foreign Language Integration — the gRPC bridge and every client SDK.

A standalone hub in Node

Define the hub

Run it as the node kernel

Related