如何在node.js中构造特定查询以从mongodb获取数据？

Question

I'm using mogoosejs and have a data model:

var UserSchema = new Schema({
    username: {type: String, required: true},
    location: {type: [Number], required: true}, // [Long, Lat]
    created_at: {type: Date, default: Date.now},
    updated_at: {type: Date, default: Date.now}
});

Now on that schema I want to perform a query that will find all the users within certain area, so I did as follows:

var query = User.find({});
if(distance){
    query = query.where('location').near({ center: {type: 'Point', coordinates: [long, lat]},
    maxDistance: distance * 1609.34, spherical: true});
}

So that works super well, but now I want to add another parameter to this query - date. So I want to find all users within a specific location and that created their accound during last 16 hours... How should I modify my query to get all those results? Thanks a lot for any clues!

Answer 1

To add the date query, create a date object that represents the datetime 16 hours ago:

var start = new Date();
start.setHours(start.getHours()-16);

Use the above in your query now as:

// get coordinates [ <longitude> , <latitude> ]
var coords = [];
coords[0] = req.query.longitude;
coords[1] = req.query.latitude;
var criteria = { 
        "created_at": { "$gte": start }
        "location": {
            "$near": coords,
            "$maxDistance": distance * 1609.34
        }
    },
    query = User.find(criteria);

If the opportunity shows, use moment.js library, a super handy utility for doing manipulations like this. To use it for such scenario, you'd call the subtract() method as:

var start = moment().subtract(16, 'hours'),
    criteria = { "created_at": { "$gte": start }},
    query = User.find(criteria);