@uppy/companion/lib/server/emitter/index.js

OAuth helper and remote fetcher for Uppy's (https://uppy.io) extensible file upload widget with support for drag&drop, resumable uploads, previews, restrictions, file processing/encoding, remote providers like Dropbox and Google Drive, S3 and more :dog:

import nodeEmitter from './default-emitter.js';
import redisEmitter from './redis-emitter.js';
let emitter;
/**
 * Singleton event emitter that is shared between modules throughout the lifetime of the server.
 * Used to transmit events (such as progress, upload completion) from controllers,
 * such as the Google Drive 'get' controller, along to the client.
 */
export default function getEmitter(redisClient, redisPubSubScope) {
    if (!emitter) {
        emitter = redisClient
            ? redisEmitter(redisClient, redisPubSubScope)
            : nodeEmitter();
    }
    return emitter;
}