Multiple get request loop -NODEjs /express/strava (cannot set headers after they are sent to the client )

Question

I am working on a school project and I am using the strava API to get users activities and streams for each activity, I am though using some libraries to do this but when I try to get all activities streams using for loop I get this error cannot set headers after they are sent to the client I know there's something wrong with my code but I can't figure it out yet. If you have a better way to do this please enlighten me.

Here's the code:

router.get('/streams/:id', (req, res,done) => {
    const userc = req.user;
    const access_token = userc.access_token;

    var _ = require("underscore");
    var fs = require("fs");
    const ids = [5312632886,
        5307798051,
        5301826997,
        5301821600,
        5283410624,
        3477443042]
    for (let i = 0; i < ids.length ; i++) {
        strava = new stravaApi.client(access_token);
        strava.streams.activity({
            id: ids[i],
            types: 'time,heartrate,velocity_smooth,altitude,distance,latlng,cadence,watts,temp,moving,grade_smooth,average_speed',
            resolution: 'high'
        }, function (err, payload) {
            if (!err) {
                res.json(payload)
                console.log(payload)
                fs.writeFile("activity-streams.json", JSON.stringify(payload), err => {
                    if (err) throw err;
                    console.log("Done writing"); // Success
                });

            } else {
                console.log(err)
            }
        })
    }
})

Answer 1

I am not familiar with strava api, but as error says - you try to send response multiple times

Do not call res.json() inside loop