MongoDB + Mongoose Aggregate w/ Asnyc - mongodb

Question

I've got the following route in my express file, which takes parameters passed in from a middleware function and queries my backend MongoDB database. But for some reason, it only ever returns an empty array.
I'd like to convert the Mongoose model that allows me to use aggregate functions into async/await to conform with the rest of my code. It's online here.
module.exports = {
search: asyncWrapper(async(req, res, next) => { // Retrieve and return documents from the database.
const {
filterTarget,
filter,
source,
minDate,
maxDate,
skip,
limit,
sortBy,
sortOrder
} = req.search;
try {
const mongoData = await Model.aggregate([
{
$match: {
date: {
$gt: minDate, // Filter out by time frame...
$lt: maxDate
}
}
},
{
$match: {
[filterTarget]: filter // Match search query....
}
},
{
$set: {
[filterTarget]: { $toLower: `$${filterTarget}` } // Necessary to ensure that sort works properly...
}
},
{
$sort: {
[sortBy]: sortOrder // Sort by date...
}
},
{
$group: {
_id: null,
data: { $push: "$$ROOT" }, // Push each document into the data array.
count: { $sum: 1 }
}
},
{
$project: {
_id: 0,
count: 1,
data: {
$slice: ["$data", skip, limit]
},
}
}
])
return res.status(200).json({ data: mongoData.data || [], count: mongoData.count || 0 });
} catch (err) {
next(err);
}
})
};
For some reason, the route is only returning an empty array every time. I've double and triple checked my variables, they are not the problem.
How can I use the Mongoose.aggregate() function in an async await route?