Mongoose Document Model.prototype.base API

The Model.prototype.base property of the Mongoose API is used to return the base Mongoose instance the model uses.

Syntax:

Model_Name.base

Return Value: The Model.prototype.base property returns the base Mongoose instance the model uses.

Setting up Node.js application:

Step 1: Create a Node.js application using the following command:

npm init

Step 2: After creating the NodeJS application, Install the required module using the following command:

npm install mongoose

Project Structure: The project structure will look like this:

Example 1: In this example, we have established a database connection using mongoose and defined model over userSchema, having two columns or fields “name” and “age”. In the end, we are using the base property on the User model which will return the base instance used by the model.

• app.js: Write down the below code in the app.js file:

Steps to run the program: To run the application execute the below command from the root directory of the project:

node app.js

Output:

Base is: <ref *1> Mongoose {
 connections: [
 NativeConnection {
 base: [Circular *1],
 collections: [Object],
 models: [Object],
 config: {},
 replica: false,
 options: null,
 otherDbs: [],
 relatedDbs: {},
 states: [Object: null prototype],
 _readyState: 2,
 _closeCalled: false,
 _hasOpened: false,
 plugins: [],
 id: 0,
 _queue: [],
 _listening: false,
 _connectionString: 'mongodb://localhost:27017/geeksforgeeks',
 _connectionOptions: [Object],
 client: [MongoClient],
 '$initialConnection': [Promise]
 }
 ],
 models: { User: Model { User } },
 events: EventEmitter {
 _events: [Object: null prototype] {},
 _eventsCount: 0,
 _maxListeners: undefined,
 [Symbol(kCapture)]: false
 },
 __driver: {
 Binary: [Function: Binary] {
 fromExtendedJSON: [Function (anonymous)],
 BSON_BINARY_SUBTYPE_DEFAULT: 0,
 BUFFER_SIZE: 256,
 SUBTYPE_DEFAULT: 0,
 SUBTYPE_FUNCTION: 1,
 SUBTYPE_BYTE_ARRAY: 2,
 SUBTYPE_UUID_OLD: 3,
 SUBTYPE_UUID: 4,
 SUBTYPE_MD5: 5,
 SUBTYPE_ENCRYPTED: 6,
 SUBTYPE_COLUMN: 7,
 SUBTYPE_USER_DEFINED: 128
 },
 Collection: [Function: NativeCollection],
 Decimal128: [Function: Decimal128] {
 fromString: [Function (anonymous)],
 fromExtendedJSON: [Function (anonymous)]
 },
 ObjectId: [Function: ObjectId] {
 getInc: [Function (anonymous)],
 generate: [Function (anonymous)],
 createPk: [Function (anonymous)],
 createFromTime: [Function (anonymous)],
 createFromHexString: [Function (anonymous)],
 isValid: [Function (anonymous)],
 fromExtendedJSON: [Function (anonymous)],
 index: 15789560
 },
 ReadPreference: [Function: readPref],
 getConnection: [Function (anonymous)]
 },
 options: {
 pluralization: true,
 autoIndex: true,
 autoCreate: true,
 [Symbol(mongoose:default)]: true
 },
 _pluralize: [Function: pluralize],
 Schema: [Function: Schema] {
 reserved: [Object: null prototype] {
 validate: 1,
 toObject: 1,
 save: 1,
 remove: 1,
 populated: 1,
 isNew: 1,
 isModified: 1,
 init: 1,
 get: 1,
 errors: 1,
 collection: 1,
 removeListener: 1,
 listeners: 1,
 emit: 1,
 prototype: 1
 },
 Types: {
 String: [Function],
 Number: [Function],
 Boolean: [Function],
 DocumentArray: [Function],
 Subdocument: [Function],
 Array: [Function],
 Buffer: [Function],
 Date: [Function],
 ObjectId: [Function],
 Mixed: [Function],
 Decimal: [Function],
 Decimal128: [Function],
 Map: [Function],
 Oid: [Function],
 Object: [Function],
 Bool: [Function],
 ObjectID: [Function]
 },
 ObjectId: [Function: ObjectId] {
 schemaName: 'ObjectId',
 defaultOptions: {},
 get: [Function (anonymous)],
 set: [Function: set],
 _checkRequired: [Function (anonymous)],
 _cast: [Function: castObjectId],
 cast: [Function: cast],
 _defaultCaster: [Function (anonymous)],
 checkRequired: [Function (anonymous)]
 }
 },
 model: [Function (anonymous)],
 plugins: [
 [ [Function (anonymous)], [Object] ],
 [ [Function (anonymous)], [Object] ],
 [ [Function], [Object] ],
 [ [Function (anonymous)], [Object] ],
 [ [Function: trackTransaction], [Object] ]
 ],
 default: [Circular *1],
 mongoose: [Circular *1]

Example 2: In this example, we have established a database connection using mongoose and defined model over studentSchema, having three columns or fields “name”, “father_name”, and “mother_name”. In the end, we are using base property on the Student model which will return base instance of the model.

• app.js: Write down the below code in the app.js file:

Steps to run the program: To run the application execute the below command from the root directory of the project:

node app.js

Output:

Base is: <ref *1> Mongoose {
 connections: [
 NativeConnection {
 base: [Circular *1],
 collections: [Object],
 models: [Object],
 config: {},
 replica: false,
 options: null,
 otherDbs: [],
 relatedDbs: {},
 states: [Object: null prototype],
 _readyState: 2,
 _closeCalled: false,
 _hasOpened: false,
 plugins: [],
 id: 0,
 _queue: [],
 _listening: false,
 _connectionString: 'mongodb://localhost:27017/geeksforgeeks',
 _connectionOptions: [Object],
 client: [MongoClient],
 '$initialConnection': [Promise]
 }
 ],
 models: { Student: Model { Student } },
 events: EventEmitter {
 _events: [Object: null prototype] {},
 _eventsCount: 0,
 _maxListeners: undefined,
 [Symbol(kCapture)]: false
 },
 __driver: {
 Binary: [Function: Binary] {
 fromExtendedJSON: [Function (anonymous)],
 BSON_BINARY_SUBTYPE_DEFAULT: 0,
 BUFFER_SIZE: 256,
 SUBTYPE_DEFAULT: 0,
 SUBTYPE_FUNCTION: 1,
 SUBTYPE_BYTE_ARRAY: 2,
 SUBTYPE_UUID_OLD: 3,
 SUBTYPE_UUID: 4,
 SUBTYPE_MD5: 5,
 SUBTYPE_ENCRYPTED: 6,
 SUBTYPE_COLUMN: 7,
 SUBTYPE_USER_DEFINED: 128
 },
 Collection: [Function: NativeCollection],
 Decimal128: [Function: Decimal128] {
 fromString: [Function (anonymous)],
 fromExtendedJSON: [Function (anonymous)]
 },
 ObjectId: [Function: ObjectId] {
 getInc: [Function (anonymous)],
 generate: [Function (anonymous)],
 createPk: [Function (anonymous)],
 createFromTime: [Function (anonymous)],
 createFromHexString: [Function (anonymous)],
 isValid: [Function (anonymous)],
 fromExtendedJSON: [Function (anonymous)],
 index: 8101215
 },
 ReadPreference: [Function: readPref],
 getConnection: [Function (anonymous)]
 },
 options: {
 pluralization: true,
 autoIndex: true,
 autoCreate: true,
 [Symbol(mongoose:default)]: true
 },
 _pluralize: [Function: pluralize],
 Schema: [Function: Schema] {
 reserved: [Object: null prototype] {
 validate: 1,
 toObject: 1,
 save: 1,
 remove: 1,
 populated: 1,
 isNew: 1,
 isModified: 1,
 init: 1,
 get: 1,
 errors: 1,
 collection: 1,
 removeListener: 1,
 listeners: 1,
 emit: 1,
 prototype: 1
 },
 Types: {
 String: [Function],
 Number: [Function],
 Boolean: [Function],
 DocumentArray: [Function],
 Subdocument: [Function],
 Array: [Function],
 Buffer: [Function],
 Date: [Function],
 ObjectId: [Function],
 Mixed: [Function],
 Decimal: [Function],
 Decimal128: [Function],
 Map: [Function],
 Oid: [Function],
 Object: [Function],
 Bool: [Function],
 ObjectID: [Function]
 },
 ObjectId: [Function: ObjectId] {
 schemaName: 'ObjectId',
 defaultOptions: {},
 get: [Function (anonymous)],
 set: [Function: set],
 _checkRequired: [Function (anonymous)],
 _cast: [Function: castObjectId],
 cast: [Function: cast],
 _defaultCaster: [Function (anonymous)],
 checkRequired: [Function (anonymous)]
 }
 },
 model: [Function (anonymous)],
 plugins: [
 [ [Function (anonymous)], [Object] ],
 [ [Function (anonymous)], [Object] ],
 [ [Function], [Object] ],
 [ [Function (anonymous)], [Object] ],
 [ [Function: trackTransaction], [Object] ]
 ],
 default: [Circular *1],
 mongoose: [Circular *1]

Reference: https://mongoosejs.com/docs/api/model.html#model_Model-base