A better way to implement exercise tracker?

JavaScript
1

Hi, FCC folks. I just finished the exercise tracker project for the APIs and Microservices certification, and while my code passes all the tests, the way I went about implementing the last requirement, (“I can retrieve part of the log of any user by also passing along optional parameters of from & to or limit. (Date format yyyy-mm-dd, limit = int),”) is pretty ugly, and I know there must be a better way to go about this using Mongoose queries. My model for each user is as follows:

let exerciseSchema = new mongoose.Schema({
  description: { type: String, required: true },
  duration: { type: Number, required: true },
  date: { type: Date, default: Date.now()}
});

let userSchema = new mongoose.Schema({
  username: { type: String, required: true, unique: true },
  _id: { type: String, default: shortid.generate },
  exercises: [exerciseSchema]
});

let User = mongoose.model("User", userSchema);

My “/api/exercise/log” code looks like this:

app.get('/api/exercise/log', (req, res) => {
  let log = [];
  let qLimit = req.query.limit;
  let qFrom = req.query.from;
  let qTo = req.query.to;
  User.findOne({_id: req.query.userId}, (err, data) => {
    if (err) {
      res.send(err);
    }
    log = data.exercises.slice();
    if (qFrom && !qTo) {
      log = log.filter(item => new Date(item.date).getTime() > new Date(qFrom).getTime());
    } else if (!qFrom && qTo) {
      log = log.filter(item => new Date(item.date).getTime() < new Date(qTo).getTime());
    } else if (qFrom && qTo) {
      log = log.filter(item => new Date(item.date).getTime() > new Date(qFrom).getTime() 
                    && new Date(item.date).getTime() < new Date(qTo).getTime());
    }
    if (qLimit) {
      log = log.slice(0, qLimit);
    }
    res.send({
      username: data.username, 
      _id: data._id, 
      count: data.exercises.length,
      log: log
    });
  })
})

This doesn’t strike me as the “right” way to do this, but I’m a little lost on how I could have used the built-in Mongoose query stuff on a sub-schema like I have here.
The challenge: https://www.freecodecamp.org/learn/apis-and-microservices/apis-and-microservices-projects/exercise-tracker
My full project: https://glitch.com/edit/#!/luos-fcc-exercise-tracker?path=server.js:138:0

Thanks for your time!