generic-mongodb-services

Implements basic Crud services for a collection using the native mongodb server.

Motivation

The idea behind this module is to avoid code repetition in the service layer of a NodeJS API. It is pretty common to separate all interaction with the DB behind a service layer, but it usually results in copy/pasting Crud operations from one service file from another. The package was develop to standarize this Crud operations and save development/maintance time.

How to install

npm install --save generic-mongodb-services

GenericCrudService

Main implementation class.

Parameters:

• {MongoClient} client: A MongoClient instance from the NodeJS MongoDB driver. Can be already connected or not when initializing, but it has to be connected when performing any operations.
• {String} databaseName: The database name
• {String} collectionName: The collection name

Methods

list(query, limit, skip, sort, projection)

---

Returns the quizzes that satisfy a query.

Params:

• {Object} query: MongoDB query.
• {Number} limit: Used for pagination. Defines how many documents can fit in the result set.
• {Number} skip: Used for pagination. Defines how many documents of the result query must be skipped before returing the objects.
• {Object} sort: MongoDB sort options.
• {Object} projection: Used for projection. Defines which fields of the objects must be returned. Useful for optimizing queries.

Example:

const objects = await service.list(
  { name: /a/i },
  5,
  5,
  { name: 1 },
  { _id: 1 }
);

count(query)

---

Returns the count of documents that satisfy a query.

Params:

• {Object} query: MongoDB query.

Example:

const count = await service.count({ name: /a/i });

exists(query)

---

Verifies if an object exists or not.

Params:

• {Object} query: MongoDB query.

Example:

const exists = await service.exists({ name: /a/i });

create(query)

---

Creates a document and returns it.

Params:

• {Object} document: JSON document to be stored in MongoDB.

Example:

const object = await service.create({
  name: "foo"
});

get(query)

---

Obtains the document with the given _id.

Params:

• {Object} query: MongoDB query.
• {Object} projection: Used for projection. Defines which fields of the objects must be returned. Useful for optimizing queries.

Example:

const object = await service.get({ validId }, { _id: 0 });

update(\query, update, options = {})

---

Generic update service for all MongoDB Operators.

Params:

• {Object} query: MongoDB query.
• {Object} update: MongoDB update operations objects. Useful for optimizing queries.
• {Object} [options={}]: MongoDB Options

Example:

const object = await service.update({ _id: validId },, {
  $unset: {
    name: ""
  }
});
const object1 = await service.updateById(validId,
  $unset: {
    name: ""
  });

patch(\query, update, options = {})

---

Partially updates a document. It only sets the sent fields. Uses the $set operator.

Params:

• {Object} query: MongoDB query.
• {Object} data: The data to be updated.
• {Object} [options={}]: MongoDB Options

Example:

const object = await service.patch(
  { _id: validId },
  {
    type: "ugly"
  }
);
const object1 = await service.patchById(validId, {
  type: "ugly"
});

remove(_id, options = {})

---

Deletes a document.

Params:

• {Object} query: MongoDB query.
• {Object} [options={}]: MongoDB Options

Example:

const object = await service.remove({ _id: validId });
const object1 = await service.removeById(validId);

listSubdocuments(_id, embeddedField, as = "item", query = {})

---

Obtains a list of subdocuments. Can be filtered using the $filter aggregation pipeline.

Params:

• {ObjectId|String} _id: The MongoDB Id of the requested document
• {String} embeddedField: The name of the subdocument array field
• {String} as: alias used by $filter for each element of the list, used to interpret the filter
• {Object} query: Filters applied to the $filter aggregation

Example:

const objects = await service.listSubdocuments(
  validId,
  validEmbbededField,
  "like",
  { $eq: ["$$like.name", "games"] }
);

getSubdocument(_id, embeddedField, query, projection = {})

---

Obtains a single subdocument of a requested document. If many subdocuments match the query, only the first one will be returned. It uses the $elemMatch operator

Params:

• {ObjectId|String} _id: The MongoDB Id of the requested document
• {String} embeddedField: The name of the subdocument array field
• {Object} query: The query used to search for the subdocument to be pulled
• {Object} [projection={}]: MongoDB projection object

Example:

const object = await service.getSubdocument(validId, validEmbbededField, {
  name: "games"
});

addSubdocument(_id, embeddedField, data, options = {})

---

Partially updates a sub document.

Params:

• {ObjectId|String} _id: The MongoDB Id of the requested document
• {String} embeddedField: The name of the subdocument array field
• {Object} query: The query used to search for the subdocument to be pulled
• {Object} data: The data to be updated
• {Object} [options={}]: MongoDB Options

Example:

const subdocument = await service.getSubdocument(validId, validEmbbededField, {
    name: "games"
  }),
  object = await service.patchSubdocument(
    validId,
    validEmbbededField,
    {
      _id: new ObjectId(subdocument._id)
    },
    {
      name: "trouble"
    }
  );

patchSubdocument(_id, embeddedField, query, data, options = {})

---

Adds a new subdocument to a subdocument array field. It accepts both primitives and objects. If an object is passed, a _id parameter is added. Uses the $push operator.

Params:

• {ObjectId|String} _id: The MongoDB Id of the requested document
• {String} embeddedField: The name of the subdocument array field
• {Object} data: The data to be added to the subdocument array field
• {Object} [options={}]: MongoDB Options

Example:

const object = await service.patchSubdocument(
  validId,
  validEmbbededField,
  { name: "foo" },
  {
    name: "trouble"
  }
);
 
const object1 = await service.patchSubdocumentById(
  validId,
  validEmbbededField,
  subdocument._id,
  {
    name: "trouble"
  }
);

removeSubdocument(_id, embeddedField, data, options = {})

---

Removes a subdocument from a subdocument array field. Uses the $pull operator.

Params:

• {ObjectId|String} _id: The MongoDB Id of the requested document
• {String} embeddedField: The name of the subdocument array field
• {Object} query: The query used to search for the desired document
• {Object} [options={}]: MongoDB Options

Example:

const object = await service.removeSubdocument(validId, validEmbbededField, {
  name: "games"
});
 
const object1 = await service.removeSubdocumentById(
  validId,
  validEmbbededField,
  subdocument._id
);

Usage

cats.service.js

const { database, collections } = require("../config/mongodb"),
  mongodb = require("../utils/mongodb"),
  { GenericCrudService } = require("generic-mongodb-services");
 
module.exports = new GenericCrudService(mongodb.client, database, "cats");

cats.routes.js

const catService = require("./cats.service");
 
async function method(query, limit, skip, sort, projection) {
  return await catService.list(query, limit, skip, sort, projection);
}

AuditedCrud

---

A subclass of the GenericCrudService that stores audit registers in write operations (create, patch, update). Takes the same parameters a GenericCrudService and an additional one. Also, all operations recieve a optional user parameters that will be stored in the database

Parameters:

• {String} [auditCollectionName='audits']: The name of the collection where the audits will be stored

¿Need to add operations? ¡No problem!

Just subclass one the desired classes and add more operations to the class

const { database, collections } = require("../config/mongodb"),
  mongodb = require("../utils/mongodb"),
  { GenericCrudService } = require("generic-mongodb-services");
 
class CustomCatService extends GenericCrudService {
  customMethod() {}
}
 
module.exports = new CustomCatService(mongodb.client, database, "cats");