demultiplexDataPublisher

demultiplexDataPublisher<TDataPublisher, TChannelName>(publisher, sourceChannelName, messageTransformer): DataPublisher

Given a channel that carries messages for multiple subscribers on a single channel name, this function returns a new DataPublisher that splits them into multiple channel names.

Type Parameters

Parameters

Returns

DataPublisher

Example

Imagine a channel that carries multiple notifications whose destination is contained within the message itself.

const demuxedDataPublisher = demultiplexDataPublisher(channel, 'message', message => {
    const destinationChannelName = `notification-for:${message.subscriberId}`;
    return [destinationChannelName, message];
});

Now you can subscribe to only the messages you are interested in, without having to subscribe to the entire 'message' channel and filter out the messages that are not for you.

demuxedDataPublisher.on(
    'notification-for:123',
    message => {
        console.log('Got a message for subscriber 123', message);
    },
    { signal: AbortSignal.timeout(5_000) },
);