Method populate

packages/core/src/entity/EntityLoader.ts:98–193

* Loads specified relations in batch. * This will execute one query for each relation, that will populate it on all the specified entities.

(
    entityName: EntityName<Entity>,
    entities: Entity[],
    populate: PopulateOptions<Entity>[] | boolean,
    options: EntityLoaderOptions<Entity, Fields>,
  )

   * This will execute one query for each relation, that will populate it on all the specified entities.
   */
  async populate<Entity extends object, Fields extends string = never>(
    entityName: EntityName<Entity>,
    entities: Entity[],
    populate: PopulateOptions<Entity>[] | boolean,
    options: EntityLoaderOptions<Entity, Fields>,
  ): Promise<void> {
    if (entities.length === 0 || Utils.isEmpty(populate)) {
      return this.setSerializationContext(entities, populate, options);
    }

    const meta = this.#metadata.find(entityName)!;

    if ((entities as AnyEntity[]).some(e => !e.__helper)) {
      const entity = entities.find(e => !Utils.isEntity(e));
      throw ValidationError.notDiscoveredEntity(entity, meta, 'populate');
    }

    const references = entities.filter(e => !helper(e).isInitialized());
    const visited = ((options as Dictionary).visited ??= new Set<AnyEntity>());
    options.where ??= {} as FilterQuery<Entity>;
    options.orderBy ??= {};
    options.lookup ??= true;
    options.validate ??= true;
    options.refresh ??= false;
    options.convertCustomTypes ??= true;

    if (references.length > 0) {
      await this.populateScalar(meta, references, { ...options, populateWhere: undefined } as any);
    }

    populate = this.normalizePopulate<Entity>(
      entityName,
      populate as true,
      options.strategy as LoadStrategy | undefined,
      options.lookup,
      options.exclude as unknown as string[],
    );
    const invalid = populate.find(({ field }) => !this.#em.canPopulate(entityName, field));

    /* v8 ignore next */
    if (options.validate && invalid) {
      throw ValidationError.invalidPropertyName(entityName, invalid.field);
    }

    this.setSerializationContext(entities, populate, options);

    const addedToVisited: AnyEntity[] = [];

    for (const entity of entities) {
      if (visited.has(entity as AnyEntity)) {
        continue;
      }

      addedToVisited.push(entity as AnyEntity);
      visited.add(entity);
    }

    for (const pop of populate) {