mongoose-subquery

mongoose-subquery provides a new $subquery operator to make a query on a reference document field.

Installation

The mongoose-subquery module adds a method to decode $subquery operator in your queries. By default, the plugin bind this method with all pre middlewares to automatically decode the input payload. However, you can configure the plugin to prevent binding some middlewares and then calling the Query.decodeSubquery function.

import mongooseSubquery from "mongoose-subquery";

const schema = new mongoose.Schema({
    ...
});
schema.plugin(mongooseSubquery, { ...options });

Configuration

interface MongooseSubqueryOptions {
  beforeDecode?: (query: mongoose.Query<any, any, any, any>, obj: object) => void | Promise<void>;
  initQuery?: (query: mongoose.Query<any, any, any, any>, key: string, obj: object, modelName: string) => void | Promise<void>;
  resolve?: (subquery: mongoose.Query<any, any, any, any>, query: mongoose.Query<any, any, any, any>) => any | Promise<any>;
  bindHooks?: string[];
}

const defaultOptions: MongooseSubqueryOptions = {
  resolve: (subquery) => subquery.find(),
  bindHooks: [
    "count",
    "countDocuments",
    "deleteMany",
    "deleteOne",
    "estimatedDocumentCount",
    "find",
    "findOne",
    "findOneAndDelete",
    "findOneAndRemove",
    "findOneAndReplace",
    "findOneAndUpdate",
    "remove",
    "replaceOne",
    "update",
    "updateOne",
    "updateMany",
  ],
};

beforeDecode

The beforeDecode function is executed when the initial query (with $subquery within conditions) is decoded

initQuery

You can provide a initQuery function that will be called each time a new mongoose.Query is instantiate by mongoose-subquery

schema.plugin(mongooseSubquery, {
    initQuery: (query, key, obj, modelName) => {
        console.log(`new query created on ${modelName} with conds ${query.getQuery()}`);
    }
});

resolve

The resolve option allows you to override the default behavior that simply run a subquery.find(), for more complex operations

schema.plugin(mongooseSubquery, {
    resolve: async (subquery) => {
        const countQuery = subquery.clone();
        const count = await countQuery.estimatedDocumentCount();
        
        if (count > 100) {
            throw new Error(`This query returns too many docs`);
        }
        
        return await subquery.find();
    }
});

Example

const roleSchema = new Schema({
  name: String,
  admin: Boolean
});
const Role = mongoose.model('Role', roleSchema, 'Roles');

const ruleSchema = new Schema({
  role: { type: ObjectId, ref: 'Role' }
});
ruleSchema.plugin(require('mongoose-subquery'));
const Rule = mongoose.model('Rule', ruleSchema, 'Rules');

Rule.find({ role: { $subquery: { admin: true } } });

Will return all rules where the referenced role matches the subquery { admin: true }