NodeJS concurrent requests response is mixed

Question

When concurrent requests are made the response data is mixed.

The route controller injects the dependencies to the use-case functions.

Route controller

const fromAdaptReq = require('../../utils/adapt-req');
...other imports

router.get('/v1/getList', async (req, res, next) => {
    try {
        const request = {
                      locals: res.locals,
                      lang: res.locals.lang
                     };

        const userCase = new fromUsersCase
            .user
            .user
            .getList({
                createError: customError.CustomError,
                translate,
                request: request,
                db: fromDB.database,
            });
        const result = await userCase.execute();
        return res.status(200).json({
            msg: result.msg,
            data: result.data,
            error: false
        });
    } catch (error) {
        console.log(error)
        next(error);
    }
}

Search listing function is used to call the query function

search listing function

exports.getList = function ({ createError, translate, request, db }) {
    return Object.freeze({
        execute: async () => {
            try {
                const userId = parseInt(request.locals.userId);

                const searchList= await fromServices
                                        .getPhonebook(request.lang, createError, translate, { userId, db });

                return {
                    msg: 'List',
                    data: { list: searchList}
                }
            } catch (error) {
                if (error instanceof createError) {
                    throw error;
                }
                console.log(error);
                throw new Error(error.message);
            }
        }
    })
}

Answer 1

I found that I was using the global variable to store the user-id inside the fromService function which was performing the query based on user id to generate the list.

Changing blocked scope fixed the error Thank you