typescript source code of database.service

// src/services/database.service.ts
import {inject, injectable} from 'inversify';
import {Connection, createConnection, ObjectType} from 'typeorm';
import {TYPES} from '../core/types.core';
import {Logger} from './logger.service';

@injectable()
export class DatabaseService {
  private static connection: Connection;

  public constructor(@inject(TYPES.Logger) private readonly logger: Logger) {}

  public async getConnection(): Promise<Connection> {
    if (DatabaseService.connection instanceof Connection) {
      return DatabaseService.connection;
    }
    // const options = await getConnectionOptions(`orm_${new Date().getTime()}`);

    try {
      DatabaseService.connection = await createConnection();
      this.logger.log('INFO', `Connection established`);
    } catch (e) {
      this.logger.log('ERROR', 'Cannot establish database connection');
      process.exit(1);
    }

    return DatabaseService.connection;
  }

  public async getRepository<T>(repository: ObjectType<T>): Promise<T> {
    const connection = await this.getConnection();
    return await connection.getCustomRepository<T>(repository);
  }
}