Sempervirens DAO

A connection manager for MongoDB using Mongoose, it provides a simplified interface for creating connections to one or more MongoDB databases and accessing models.

Installation

npm i @sempervirens/dao

Usage

Install MongoDB

1. Find your OS, download, install from Install MongoDB.
2. (Optional) Include MongoDB Compass (free DB visualization) when installing MongoDB, or Install MongoDB Compass later.

Create Mongoose Schemas

1. Create a directory.
2. Create Mongoose schemas within the directory.

/app/src/schemas/test-schema.js

const testSchema = new mongoose.Schema({
  prop1: { type: String },
  prop2: { type: Number }
});
export default testSchema;

Configure and Initialize

1. Import @sempervirens/dao into the app's entrypoint.
2. Import the schemas.
3. Call dao.config. connectionOptions are the Mongoose connection options.
4. Call dao.initDb for each database.

Note 1: Only call dao.config once in one place, and only call dao.initDb in one place, for each database.
Note 2: Multi-host connections are possible by passing host, port, and connectionOptions into initDb instead of config.

/app/src/index.js

import dao from '@sempervirens/dao';
import testSchema from './schemas/testSchema.js';

// Call only once
dao.config({
  host: 'localhost',
  port: '27017',
  connectionOptions: {
    useNewUrlParser: true,
    useUnifiedTopology: true
  }
});

// Call for each DB
dao.initDb({
  name: 'testdb1',
  models: [
    { name: 'Test1', schema: testSchema }
  ]
});

// Connect to a different host
dao.initDb({
  host: 'anotherhost',
  port: 'anotherport',
  connectionOptions: {},
  name: 'testdb2',
  models: [
    { name: 'Test2', schema: testSchema }
  ]
});

Access Models

1. Import @sempervirens/dao where access to models is needed.
2. Call methods on dao and dao databases to access models
3. Call Mongoose methods on models.

/app/src/example.js

import dao from '@sempervirens/dao';

// Any async function (doesn't have to be anonymous self-calling)
(async function() {

  // Access using dao's getModel
  const Test1a = dao.getModel('testdb', 'Test1');
  const docsA = await Test1a.find();

  // Access using DB's getModel
  const db = dao.getDb('testdb');
  const Test1b = db.getModel('Test1');
  const docsB = await Test1b.find();

})();

API

dao (Singleton instance)

Prop	Type	Params	Description
config	Function	{ host = 'localhost', port = '27017', connectionOptions = {} }	Configures the dao object with host, port, and connectionOptions.
initDb	Function	{ name = '', models = [{ name = '', schemas = new mongoose.Schema() }] }	Connects to a database, adds the database to dao.dbs, creates each model, and attaches each model to dao.dbs.dbName.models
dbs	Object	n/a	A literal key: value object where key is the database name given in initDb, and value is a Db instance.
getDb	Function	dbName = ''	Gets a database from the dao.dbs map. Equivalent to dao.dbs.dbName.
getModel	Function	dbName = '', modelName = ''	Gets a model from the dao.dbs.dbName.models map. Equivalent to dao.dbs.dbName.models.modelName.

Db (class)

Prop	Type	Params	Description
name	String	n/a	Name of the database.
connection	Object	n/a	The Mongoose connection object.
models	Object	n/a	A literal key: value object where key is the model name given in initDb and value is a Mongoose Model.
getModel	Function	modelName = ''	Gets a model from the db.models map. Equivalent to db.models.modelName.