Usage with JavaScript

Since MikroORM 3.2, we can use EntitySchema helper to define own entities without decorators, which works also for Vanilla JavaScript.

Read more about EntitySchema in this section.

Here is an example of such entity:

./entities/Author.js

const { Collection, EntitySchema } = require('@mikro-orm/core');
const { Book } = require('./Book');
const { BaseEntity } = require('./BaseEntity');

/**
 * @property {number} id
 * @property {Date} createdAt
 * @property {Date} updatedAt
 * @property {string} name
 * @property {string} email
 * @property {number} age
 * @property {boolean} termsAccepted
 * @property {string[]} identities
 * @property {Date} born
 * @property {Collection<Book>} books
 * @property {Book} favouriteBook
 * @property {number} version
 * @property {string} versionAsString
 */
class Author extends BaseEntity {

  /**
   * @param {string} name
   * @param {string} email
   */
  constructor(name, email) {
    super();
    this.name = name;
    this.email = email;
    this.books = new Collection(this);
    this.createdAt = new Date();
    this.updatedAt = new Date();
    this.termsAccepted = false;
  }

}

export const schema = new EntitySchema({
  class: Author,
  properties: {
    name: { type: 'string' },
    email: { type: 'string', unique: true },
    age: { type: 'number', nullable: true },
    termsAccepted: { type: 'boolean', default: 0, onCreate: () => false },
    identities: { type: 'string[]', nullable: true },
    born: { type: DateType, nullable: true, length: 3 },
    books: { reference: '1:m', entity: () => 'Book', mappedBy: book => book.author },
    favouriteBook: { reference: 'm:1', type: 'Book' },
    version: { type: 'number', persist: false },
  },
});

module.exports.Author = Author;
module.exports.entity = Author;
module.exports.schema = schema;

Do not forget to provide name and path schema parameters as well as entity and schema exports.

Reference parameter can be one of (where SCALAR is the default one):

export enum ReferenceType {
  SCALAR = 'scalar',
  ONE_TO_ONE = '1:1',
  MANY_TO_ONE = 'm:1',
  ONE_TO_MANY = '1:m',
  MANY_TO_MANY = 'm:n',
  EMBEDDED = 'embedded',
}

You can register your entities as usual.

const orm = await MikroORM.init({
  entities: [Author, Book, BookTag, BaseEntity],
  dbName: 'my-db-name',
  type: 'mysql',
});

For more examples of plain JavaScript entity definitions take a look Express JavaScript example.