Relationships in objection.js

Now I need a list of tickets but including the information of their type. Looks like it is a work for the eager method.

Define Relations in Objection

First I need to tell Objection.js how my tables are related. For this I need to use the relationMappings
method who will need an object with the definition of all my relationships.
In this case I only need one relationship since a ticket has one type.

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const { Model } = require('objection');

class Ticket extends Model {
	static get tableName() {
		return 'ft_tickets';
	}

	static get relationMappings() {
		return {
			type: {
				relation: Model.HasOneRelation,
				modelClass: `${__dirname}/TicketType.js`,
				join: {
					from: 'ft_tickets.type_id',
					to: 'ft_ticket_types.id',
				},
			},
		};
	}
}

module.exports = Ticket;

This is my Ticket Model, inside the relationMappings function I have defined an object called type. This name can be anything I want, but since a ticket can have a type looks like a good name 😅
Now I will define what kind of relation the tables has. In this case I will use the HasOneRelation value.
Good, the second information objection needs is the path to the Model what I want to relate my current Model.
It can be a relative or absolute path, I like absolute paths so I am using the __dirname variable.
Now the join method will contain the fields who define the relation between the tables. In this case the table ft_tickets has the type_id field and this field is related with the ID of the ft_ticket_types table.

The eager function

Finally I can use the eager method to make a query including the relationship.

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Ticket.query()
	.eager('type')
	.select('id', 'number', 'type_id')
	.then(tickets => {
		console.log('Types', tickets);
	});

The eager method takes as a parameter the name of the relationship who has been defined in the relationMappings function. Since I choose the name type in there I must use the same name inside the eager method.
Inside the then method I now have an array of tickets and every ticket has an type object with the information of the ticket type.❣️