Example from https://github.com/thefrontside/effection/issues/662#issuecomment-1243863041

main.mjs

import { google } from 'googleapis'
import { Firestore } from '@google-cloud/firestore'
import { main, createQueue } from 'effection';
import "path"
import _ from "lodash"




class DB {
    constructor() {
      this.firestore = new Firestore()
      this.name = "meta/meta";
    }
    *init() {
        const metaDoc = doc(this.firestore, "meta/meta")
        let snapshot = yield getDoc(metaDoc)
    }
    *get(path, id) {
        docRef = doc(this.firestore, path, id)
        docSnp = yield getDoc(docRef)
        return docSnp.exists ? docSnp : null
    }
}



function* dereferencePages(data, apiMethod, apiParams) {
    while (true) {
        if (!("nextPageToken" in data))
            break
        apiParams.pageToken = response.data.nextPageToken
        response = yield apiMethod(apiParams)
        data = { ...response.data }
    }
}


function* getWithCache(db, apiMethod, apiParams, id) {
    let headers = {}
    let cache = db.firestore.collection("cache")
    let cached_ref = cache.doc("id")
    let cached_doc = yield cached_ref.get()

    if (cached_doc.exists) {
        if (_.get(cached_doc, "videosdb.etag")) {
            headers["If-None-Match"] = cached_doc.videosdb.etag
        }
    }

    apiParams.headers = headers

    let response = yield apiMethod(apiParams)

    let result = null
    switch (response.status) {
        case 304:
            result = {
                doc: cached_doc,
                modified: false
            }
            break
        default:
            let full_data = dereferencePages(response.data, apiMethod, apiParams)
            let doc_ref = cache.doc(id)
            yield doc_ref.set(full_data.items)

            result = {
                doc: full_data,
                modified: true
            }
    }


    return result
}

class PlaylistRetriever {
    constructor(db, api, queue) {
        this.db = db
        this.queue = queue
        this.api = api

    }
    *start() {
        let channel_id = process.env.YOUTUBE_CHANNEL_ID
        let params = {
            "part": "snippet,contentDetails,statistics",
            "id": channel_id
        }
        console.info("Retrieving channel " + channel_id)
        let method = this.api.channels.list.bind(this.api)
        let channel_info = yield getWithCache(this.db,
            method,
            params,
            channel_id)
        console.debug(channel_info)

        this.YT_CHANNEL_NAME = channel_info.snippet.title
        let doc = this.db.firestore.doc("channel_infos/" + channel_id)

        yield doc.set(channel_info, { merge: true })
        let playlist_ids = null
        if (process.env.DEBUG) {
            let params = {
                "part": "contentDetails",
                "channelId": channel_id
            }
            let response = yield this.api.channelSections.list(params)

        }
        let playlistQueue = createQueue("Playlist queue")

    }

}

class Downloader {
    constructor(exclude_transcripts = false) {
        this.valid_video_ids = []
        this.db = new DB()
        this.api = google.youtube({
            version: 'v3',
            auth: process.env.YOUTUBE_API_KEY
        })
    }
    *check_for_new_videos() {
        console.info("Sync start")
        let retriever = new PlaylistRetriever(this.db, this.api)

        yield retriever.start()
        console.info("Sync finished")
        return true

    }
}

main(function* () {
  let d = new Downloader()
  let result = yield d.check_for_new_videos()
  console.info("RESULT: " + result)
});

package.json

{
    "name": "backend",
    "version": "1.0.0",
    "main": "index.js",
    "license": "MIT",
    "private": true,
    "dependencies": {
        "@google-cloud/firestore": "^6.0.0",
        "effection": "^2.0.4",
        "googleapis": "^107.0.0",
        "lodash": "^4.17.21",
        "slugify": "^1.6.5"
    },
    "type": "module",
    "scripts": {
        "start": "node app.js"
    }
}