database/services/Factory.js

//--------------------------------------------------------
//-- Node IoC - Database - Services - Factory
//--------------------------------------------------------

import __ from '@absolunet/private-registry';


/**
 * Factory service that helps build factoried model instances through defined model factories.
 *
 * @memberof database.services
 * @hideconstructor
 */
class Factory {

	/**
	 * Class dependencies: <code>['app', 'db.model', 'faker']</code>.
	 *
	 * @type {Array<string>}
	 */
	static get dependencies() {
		return ['app', 'db.model', 'faker'];
	}

	/**
	 * @inheritdoc
	 * @private
	 */
	init() {
		__(this).set('factories', {});
	}

	/**
	 * Get model factory instance by name.
	 *
	 * @param {string} name - The model factory name.
	 * @returns {database.Factory} The model factory instance.
	 */
	get(name) {
		const factory = __(this).get('factories')[name];

		if (!factory) {
			throw new TypeError(`Cannot find factory for model [${name}].`);
		}

		return factory;
	}

	/**
	 * Make a model with attributes from its associated factory.
	 *
	 * @example
	 * factory.make('user'); // User { name: "John Smith", email: "john.smith@example.com" }
	 * factory.make('user', { name: 'John Doe' }); // User { name: "John Doe", email: "john.smith@example.com" }
	 * factory.make('user', 3); // Collection { [User { name: 'John Smith', email: 'john.smith@example.com }, User { ... }, User { ... }] }
	 * factory.make('user, { name: 'John Doe' }, 2); // Collection { []User { name: 'John Doe', email: 'johm.smith@example.com' }, User { ... }] }
	 *
	 * @param {string} model - The model name.
	 * @param {object<string, *>|number} [parameters={}] - The parameters to put into the model manually, overwriting matching factoried values. Can also be the times if no parameter are given.
	 * @param {number} [times=1] - The quantity of models that needed to be factoried. Minimum 1 model is required.
	 * @returns {Model|Collection} Either a single Model instance or a Model Collection instance, containing N times the requested model.
	 */
	make(model, parameters = {}, times = 1) {
		const ModelInstance = __(this).get('db.model').get(model);
		const factory       = this.get(model);
		const count         = typeof parameters === 'number' ? parameters : times;
		const properties    = typeof parameters === 'number' ? {} : parameters;

		if (count <= 0) {
			throw new TypeError('Cannot make less than one model.');
		}

		const models = [...new Array(count).keys()].map(() => {
			return new ModelInstance({ ...factory.make(), ...properties });
		});

		return count === 1 ? models[0] : ModelInstance.collection(models);
	}

	/**
	 * Register factory for a given model.
	 * If the model name is not provided, it will be taken from the factory instance.
	 *
	 * @param {database.Factory} factory - The factory class.
	 * @param {string|null} [model] - The model name. If no value is provided, the factory model will be taken.
	 * @returns {database.services.Factory} The factory service instance.
	 */
	register(factory, model = null) {
		const instance = this.app.make(factory, { faker: this.app.make('faker') });
		__(this).get('factories')[model || instance.model] = instance;

		return this;
	}

}


export default Factory;