Overview

Moves frame payloads between the app and a Companion radio behind one Transport interface: TcpTransport (WiFi), SerialTransport (USB), BleTransport. The @meshcorejs/transports/mock subpath ships MockTransport (in-memory) and FakeRadio (a firmware emulator) used by every test in the monorepo.

interface Transport extends TypedEmitter<{ frame: [Uint8Array]; close: [Error?] }> {
  readonly kind: 'serial' | 'tcp' | 'ble' | 'mock';
  readonly connected: boolean;
  connect(signal?: AbortSignal): Promise<void>;
  write(payload: Uint8Array): Promise<void>;
  close(): Promise<void>;
}

What a transport does

• Moves payloads: write(payload) sends one frame payload, frame events deliver one payload each.
• Adds and strips the framing for its medium (serial/TCP: '<'/'>' | len u16 LE; BLE: one write or notification is already one frame, no header).
• Emits close only for an unexpected loss, never after the app itself called close().

What a transport does not do

No reconnection, no protocol knowledge, no queueing of outgoing writes: the Client in @meshcorejs/client owns all of that. A transport is a dumb pipe for bytes; everything stateful about the bot's session lives one layer up.

Reference

• Transport
• TransportEvents
• TypedEmitter