LoopBack types

Overview

Various LoopBack methods accept type descriptions, for example remote methods and  dataSource.createModel().

The following table summarizes LoopBack’s data types.

new Buffer(42);

new GeoPoint({lat: 10.32424, lng: 5.84978});

{ "firstName": "John", "lastName": "Smith", "age": 25 }

In general, a property will have undefined value if no explicit or default value is provided.

Array types

LoopBack supports array types as follows:

• {emails: [String]}
• {"emails": ["string"]}
• {"emails": [{"type": "string", "length": 64}]}
• {"emails": "array"} (a shorthand notation for {"emails": ["any"]})

Array of objects

Define an array of objects as follows (for example):

...
"Address": {
  "type": [
    "object"
  ],
  "required": true
}
...

Object types

Use the Object type when you need to be able to accept values of different types, for example a string or an array.

A model often has properties that consist of other properties. For example, the user model can have an address property that in turn has properties such as street, city, state, and zipCode. LoopBack allows inline declaration of such properties, for example:

var UserModel = {
    firstName: String,
    lastName: String,
    address: {
        street: String,
        city: String,
        state: String,
        zipCode: String
    },
    ...
}

The value of the address is the definition of the address type, which can be also considered an “anonymous” model.

If you intend to reuse the address model, define it independently and reference it in the user model. For example:

var DataSource = require('loopback-datasource-juggler').DataSource;
var ds = new DataSource('memory');

var AddressModel = {
    street: String,
    city: String,
    state: String,
    zipCode: String
};

var Address = ds.define('Address', AddressModel);

var UserModel = {
        firstName: String,
        lastName: String,
        address: 'Address',  // or address: Address
        //...
}

var User = ds.define('User', UserModel);