Mongoose Embed Middleware

Embed.middleware.ts

import { NextFunction, Request, Response } from "express";

declare module "express" {
    interface Request {
        embed: { path: String, fields?: String }[]
    }
}

export function EmbedMiddleware(req: Request, res: Response, next: NextFunction): void {
    req.embed = [];

    if (req.query.embed) {
        let embedQueries: String[] = req.query.embed.split(",");

        embedQueries.forEach(query => {
            if (query.includes(".")) {
                req.embed.push({ path: query.split(".")[0], fields: query.split(".")[1].replace("+", " ") })
            } else {
                req.embed.push({ path: query });
            }
        });
    }

    next();
}

Example.controller.ts

router.get("/", (req: Request, res, next) => {
    let query = Model.find();

    req.embed.forEach(embed => {
        query.populate(embed.path, embed.fields);
    });

    query.then(results => {
        res.send(results);
    });
});