Mongodb textScore for Loopback 4

gistfile1.txt

import {DefaultCrudRepository} from '@loopback/repository';
import {Reference, ReferenceRelations} from '../models';
import {MongoDsDataSource} from '../datasources';
import {inject} from '@loopback/core';

export class ReferenceRepository extends DefaultCrudRepository<
  Reference,
  typeof Reference.prototype.id,
  ReferenceRelations
> {
  dataSource: MongoDsDataSource;
  constructor(
    @inject('datasources.mongoDs') dataSource: MongoDsDataSource,
  ) {
    super(Reference, dataSource);
    this.dataSource = dataSource;
  }

  /**
   * Loopback 4 queries' filter syntax doesn't seem to support textScore in the order nor fields filter,
   * so we need to get the instance of mongodb's driver, in order to query directly
   * @param text
   */
  async textSearch(text) {
      return new Promise<any>((resolve, reject) => {
          if (!this.dataSource || !this.dataSource.connector) {
              return reject('No connection')
          }
          const mongodb = this.dataSource.connector;
          mongodb.collection(Reference.modelName)
              .find(
                  { $text: { $search: text } },
                  { projection: { name: true, score: { $meta: 'textScore' } } }
              )
              .sort({ score: { $meta: 'textScore' } })
              .toArray(function(err, items) {
                  if (err) {
                      return reject(err)
                  }
                  return resolve(items);
              });
      });
  }
}