pair.js

import { db } from "@models";

async function pair() {
    try {
        const matchingCollection = db.collection("matchings");

        const notMatchedArr = await matchingCollection
            .find({
                matched: false
            })
            .toArray();

        if (!notMatchedArr.length) {
            return false;
        }
        
        const bookDetailsIdsUnique = makeDistictArray(notMatchedArr);

        const queuesByBookDetails = bookDetailsIdsUnique.map(e => {
            const bookDetailQueue = notMatchedArr.filter(el => {
                return el.bookDetailId === e;
            });

            return bookDetailQueue;
        });

        queuesByBookDetails.forEach(aBookDetailQueue => {
            const returnArr = aBookDetailQueue.filter(match => !match.bookId);
            const requestArr = aBookDetailQueue.filter(match => match.bookId);

            returnArr.sort((a, b) => b.time - a.time);
            requestArr.sort((a, b) => b.time - a.time);

            const shorterLength =
                returnArr.length < requestArr.length
                    ? returnArr.length
                    : requestArr.length;

            if (!shorterLength) {
                return false;
            }

            const loopByShorterLength = Array.from(Array(shorterLength));
            loopByShorterLength.forEach((_, index) => {
                const matchedReturner = returnArr[index];
                const matchedRequester = requestArr[index];

                pairUpdateQueue.addJob(matchedReturner, matchedRequester);
            });
        });

        return true;
    } catch (err) {
        console.log("Error when pair: ", err);
        throw err;
    }
}