How to define object in array in Mongoose schema correctly with 2d geo index

How to Define Object in Array in Mongoose Schema Correctly with 2D Geo Index

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Have you ever encountered problems when creating a schema for a document in Mongoose? Do you find yourself getting stuck and frustrated when the response from the server returns "trk" field values as [Object]? 🤔 Well, fear not! In this blog post, we'll walk you through the correct way to define an object in an array in a Mongoose schema, specifically with a 2D geo index. Let's dive in!

📝 Note: The examples and solutions provided in this blog post are based on Mongoose version 3.6.20 and MongoDB 2.4.7.

The Problem

Let's first examine the original data and the Mongoose schema provided:

// Original data
{
  "_id": ObjectId("51ec4ac3eb7f7c701b000000"),
  "gpx": {
    "metadata": {
      "desc": "Nürburgring VLN-Variante",
      "country": "de",
      "isActive": true
    },
    "trk": [
      {
        "lat": 50.3299594,
        "lng": 6.9393006
      },
      {
        "lat": 50.3295046,
        "lng": 6.9390688
      },
      {
        "lat": 50.3293714,
        "lng": 6.9389939
      },
      {
        "lat": 50.3293284,
        "lng": 6.9389634
      }
    ]
  }
}

// Mongoose Schema
var TrackSchema = Schema({
  _id: Schema.ObjectId,
  gpx: {
    metadata: {
      desc: String,
      country: String,
      isActive: Boolean
    },
    trk: [{lat:Number, lng:Number}]
  }
}, { collection: "tracks" });

The issue arises when accessing the "trk" field values from the server response. Instead of getting the actual latitude and longitude values, we only see [Object] representations.

The Solution

To correct this problem, we need to adjust the Mongoose schema definition for the "trk" field. Here are three different approaches you can try:

1. Use Schema.Types.Mixed

trk: Schema.Types.Mixed

1. Use an array of Schema.Types.Mixed

trk: [Schema.Types.Mixed]

1. Specify the types and add an index for 2D geolocation

trk: [{ type: [Number], index: "2d" }]

By using any of these approaches, you will be able to define the "trk" field correctly and retrieve its values without seeing [Object] representations.

The Example

Here's an updated version of the Mongoose schema using the third approach:

var TrackSchema = Schema({
  _id: Schema.ObjectId,
  gpx: {
    metadata: {
      desc: String,
      country: String,
      isActive: Boolean
    },
    trk: [{ type: [Number], index: "2d" }]
  }
}, { collection: "tracks" });

With this schema definition, you should now be able to access the latitude and longitude values from the "trk" field without any issues.

Conclusion

Defining objects in arrays in Mongoose schemas can be a bit tricky, especially when dealing with specific requirements like a 2D geo index. However, by following the solutions mentioned in this blog post, you will be able to overcome these common issues and retrieve the values you need.

If you're still having trouble or have any questions, feel free to reach out to us in the comments section below. We're always here to help! 😊

Now it's your turn! Have you encountered similar issues in defining objects in arrays in Mongoose schemas? Share your experiences and solutions in the comments! Let's learn from each other and make our coding lives easier.

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