This is post API

router.post('/', async function(req, res, next) {
    const subscribersFile= path.join(__dirname, "../subscribers.json")
    const data = await fs.readFile(subscribersFile, "utf-8")
    let subscribers= JSON.parse(data)

    let subscriber = req.body
 
    const id = uuid.v4();
    subscriber = {...subscriber, id: id}

    subscribers = [...subscribers, subscriber]
    const json = JSON.stringify(subscribers)
    await fs.writeFile(subscribersFile, json, "utf-8")

    return res.json({data: "POST", body: req.body})
});

This code works but review comments suggested to change it to dictionary.

How to change subscribers = [...subscribers, subscriber] to a dictionary?