loopback-datasource-juggler/examples/nesting-schema.js

var ModelBuilder = require('../../loopback-data').ModelBuilder;
var modelBuilder = new ModelBuilder();

// simplier way to describe model
var User = modelBuilder.define('User', {
    name: String,
    bio: ModelBuilder.Text,
    approved: Boolean,
    joinedAt: Date,
    age: Number,
    address: {
        street: String,
        city: String,
        state: String,
        zipCode: String,
        country: String
    },
    emails: [{
        label: String,
        email: String
    }],
    friends: [String]
});

var user = new User({name: 'Joe', age: 20, address: {street: '123 Main St', 'city': 'San Jose', state: 'CA'},
    emails: [{label: 'work', email: 'xyz@sample.com'}],
    friends: ['John', 'Mary']});
console.log(user.toObject());