aggregatePipline.ts

import { AggregationOperatorsArg } from "@bageldb/bagel-db/dist/interfaces"
import { db } from "../bageldb"
// NOTE: currently only works with following version ! "@bageldb/bagel-db": "^0.4.30-beta.0.03",

const aggSteps: AggregationOperatorsArg = [
	{
		$match: {
			activeJourneyId: {
				$exists: true,
			},
		},
	},
	{
		// query from a different collection !!!
		$lookup: {
			from: "groups",
			localField: "activeGroupId",
			foreignField: "_id",
			as: "group",
		},
	},
	{
		$unwind: {
			path: "$group",
			preserveNullAndEmptyArrays: true,
		},
	},
	{
		$lookup: {
			// query from a different collection !!!
			from: "questions",
			localField: "_id",
			foreignField: "userId",
			as: "questions",
		},
	},
	{
		$project: {
			lastName: 1,
			lastLogin: 1,
			_createdDate: 1,
			bio: 1,
			trip: 1,
			_lastUpdatedDate: 1,
			nickname: 1,
			lastProfileUpdate: 1,
			ifVisited: 1,
			email: 1,
			thumbnail: 1,
			hometown: 1,
			activeGroupId: 1,
			activeJourneyId: 1,
			activeChannelUrl: 1,
			fullName: 1,
			dateOfBirth: 1,
			firstName: 1,
			userPhotos: 1,
			registrationToken: 1,
			location: 1,
			activeJourneyName: 1,
			group: {
				_id: "$group._id",
				name: "$group.name",
				description: "$group.description",
			},
			questions: 1,
		},
	},
	{
		$count: "userCount",
	},
]


export const aggCall = async () => {

	const res = await db.collection("userInfo").aggregationPipeline(aggSteps).get();


	console.log(JSON.stringify({ ...res.data }, null, 2));
	/*
	expected output:
	{
		"0": {
			"badges": [],
			"ifVisited": false,
			"image": {
				"imageName": "",
				"altText": "",
				"imageURL": "",
				"extension": ""
			},
			"isAdmin": false,
			"trip": [],
			"userCount": 1846
		}
	}
	*/
}