In a Node.js backend for a React.js app, I am using
"mongodb" (as db.version returns): "3.4.10",
"mongoose": "5.3.4"
The issue is I can't use $expr with a mongoDB version < 3.6. It seems like a lot of effort to upgrade the mongoDB version juste because of this issue (deprecated methods and so on). So I was wondering if there was a way to do what I am trying to do without using $expr ?
Here is the code :
match.$expr = {
$lt: ["$distance", "$range"] // "calculated_distance < tutor_range"
}
Would you know how ? Here is the full method, if ever you want some more details about it.
exports.search = (req, res) => {
let lat1 = req.body.lat;
let lon1 = req.body.lng;
let page = req.body.page || 1;
let perPage = req.body.perPage || 10;
let radius = req.body.radius || 10000;
let levelsIn = req.body.levels && req.body.levels.length !== 0 ? req.body.levels.map(level => {
return ObjectID(level);
}) : null;
let subjectsIn = req.body.subjects && req.body.subjects.length !== 0 ? req.body.subjects.map(subject => {
return ObjectID(subject);
}) : null;
var options = { page: page, limit: perPage, sortBy: { updatedDate: -1 } }
const isAdmin = req.user ? req.user.role === "admin" || req.user.role === "super-admin" : false;
let match = {}
if (levelsIn) match.levels = { $in: levelsIn };
if (subjectsIn) match.subjects = { $in: subjectsIn }
if (typeof req.body.activated !== "undefined") match.profileActivated = req.body.activated;
if (req.body.from) match.createdAt = { $gte: new Date(req.body.from) };
if (req.body.to) {
if (match.createdAt) match.createdAt.$lte = new Date(req.body.to);
else match.createdAt = { $lte: new Date(req.body.to) };
}
var aggregate = null;
if (!isAdmin) {
match.activated = true
match.profileActivated = true
match.profileOnline = true
}
if (lat1 && lon1) {
match.$expr = {
$lt: ["$distance", "$range"] // "calculated_distance < tutor_range"
}
aggregate = Tutor.aggregate([
{
"$geoNear": {
"near": {
"type": "Point",
"coordinates": [lon1, lat1]
},
"distanceField": "distance", // this calculated distance will be compared in next section
"distanceMultiplier": 0.001,
"spherical": true
}
},
{
$match: match
}
]);
} else {
aggregate = Tutor.aggregate([
{
$match: match
}
]);
}
Tutor
.aggregatePaginate(aggregate, options, function (err, result, pageCount, count) {
if (err) {
return res.status(400).send(err);
}
else {
var opts = [
{ path: 'levels', select: 'name' },
{ path: 'subjects', select: 'name' },
{ path: 'assos', select: 'name' }
];
Tutor
.populate(result, opts)
.then(result2 => {
return res.send({
page: page,
perPage: perPage,
pageCount: pageCount,
documentCount: count,
tutors: result2
});
})
.catch(err => {
return res.status(400).send(err);
});
}
})
};
Thank you very much for your answers and help !
