Passing a variable from React-Native to Nodejs with fetch

Question

In react-native I have this function:

export default async function get_happy_songs(param) {

    let emotion = param;
    console.log(emotion)
    let urlOfS = 'http://10.0.2.2:5000/happy_songs'
    
    return fetch(urlOfS, {
             method: 'GET'
        }).then((response) => response.json())
            .then((responseJson) => {
                console.log('response object:', responseJson)
                return responseJson;
            })
            .catch((error) => {
                console.error(error);
            });
    }

and what I want to do is pass variable "emotion" to the NodeJs backend route .../happy_songs and to be able to get this variable in the backend route and to use it there. Here is the route implementation:

app.get('/happy_songs',function(req,res) {

    var resultArray = [];
    var cursor = db.collection('songs1').find({label: "happy"},{songName:1});
    cursor.forEach(function(doc, err) {
        resultArray.push(doc);
    }, function() {
        var songsNames = [];
        for (var i = 0; i < resultArray.length; ++i) {
            songsNames.push(resultArray[i].songName);
        }
        var json_response = {melodies:songsNames}
        res.json(json_response)
})

Anyone has any idea how can I do that ?

I know it supposed to be very simple, but I am not familiar with this languages, please help me ..