API reference › @evolu/common › Worker › MessageChannel

Defined in: packages/common/src/Worker.ts:163

Platform-agnostic MessageChannel.

Creates two entangled ports: keep one and transfer the other (e.g., to a SharedWorker via postMessage with transfer). Messages sent to one port are received by the other.

Messages are queued until onMessage is assigned, enabling safe async initialization. The sender can post messages immediately while the receiver performs async setup — no manual buffering required.

For one-way communication, omit Output (defaults to never).

Example

Transfer a channel port to a SharedWorker for async initialization:

// Main thread: create channel, transfer port1, use port2 immediately.
const channel = createMessageChannel<EvoluRequest, EvoluResponse>();

sharedWorker.port.postMessage(
  { type: "CreateEvolu", port: channel.port1.native },
  [channel.port1.native],
);

// Safe to send immediately — messages queue until worker is ready.
channel.port2.postMessage({ type: "Query", query });
channel.port2.onMessage = (response) => {
  handleResponse(response);
};

// Worker: receive the port, do async init, then start listening.
const evoluPort = createMessagePort<EvoluResponse, EvoluRequest>(message.port);
await openDatabase(name);
evoluPort.onMessage = (request) => {
  handleRequest(request);
};
// Queued messages are now delivered in order.

See

https://developer.mozilla.org/en-US/docs/Web/API/MessageChannel

Extends

Extended by

Methods

[dispose]()

dispose: void;

Defined in: node_modules/.bun/typescript@5.9.3/node_modules/typescript/lib/lib.esnext.disposable.d.ts:36

Inherited from

Disposable.[dispose]

Properties

port1

readonly port1: MessagePort<Input, Output>;

Defined in: packages/common/src/Worker.ts:165

The first port of the channel.

port2

readonly port2: MessagePort<Output, Input>;

Defined in: packages/common/src/Worker.ts:168

The second port of the channel.

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