check if this will work for you. I am using it on mediabar and that donation platform.

mongodb search using index

exports.searchCreators = (req, res) => {
    var result = {};
    var query = req.body.query;

    User.find({$text: {$search: query}})
    .select("-password")
    .populate('supporters')
    .sort('-createdAt')
    .then(users => {
        result.status = "success";
        result.message = "users found";
        result.users = users;
        return res.status(200).send(result);
    })
    .catch(err => {
        console.log(err);
        result.status = "failed";
        result.message = "error occurred finding users";
        return res.status(500).send(result);
    });
}