Extract Decimal from Decimal128 with Mongoose - MongoDB

Question

I\'m querying Mongo in Nodejs with Mongoose and attempting to extract the numeric value of multiple fields stored as a Decimal128. However, the value is oddly wrapped in que

Answer 1

This will work with any field!

It supports subdocument and arrays of subdocuments too

const MySchema = new Schema({/*... schema fields ...*/});


const decimal2JSON = (v, i, prev) => {
  if (v !== null && typeof v === 'object') {
    if (v.constructor.name === 'Decimal128')
      prev[i] = v.toString();
    else
      Object.entries(v).forEach(([key, value]) => decimal2JSON(value, key, prev ? prev[i] : v));
  }
};

MySchema.set('toJSON', {
  transform: (doc, ret) => {
    decimal2JSON(ret);
    return ret;
  }
});

mongoose.model('MyModel', MySchema);

Usage:

MyModel.findOne().then(data => console.log(data.toJSON());