Knex PG Example DbCreator class

DbCreator.js

const knex = require("knex");

class DbCreator {
  /**
   *
   * Usage example:
   * const DbCreator = require('./DbCreator)
   * const dbConfigs = {
   *  host: "127.0.0.1",
   *  user: "postgres",
   *  password: "123456",
   *  charset: "utf8",
   * };
   *
   * const dbCreator = new DbCreator(dbConfigs);
   * const hasDb = await dbCreator.existsDatabase("db_name");
   * if(!hasDb) {
   *  await dbCreator.createDatabase("db_name");
   * }
   * await dbCreator.dropDatabase("db_name");
   *
   * @param {Object} dbConfigs - pg configs
   * @param {Object} dbConfigs.host - pg host
   * @param {Object} dbConfigs.user - pg user
   * @param {Object} dbConfigs.password - pg password
   * @param {Object} dbConfigs.charset - pg charset
   */
  constructor(dbConfigs) {
    this.knexConfig = {
      client: "pg",
      connection: {
        host: dbConfigs.host,
        user: dbConfigs.user,
        password: dbConfigs.password,
        charset: dbConfigs.charset || "utf8",
      },
    };
    this.knex = {};
  }

  createConnection() {
    this.destroyConnection();
    this.knex = knex(this.knexConfig);
  }

  destroyConnection() {
    this.knex.destroy && this.knex.destroy();
  }

  async existsDatabase(dbName) {
    try {
      this.createConnection();
      const query = `SELECT 1 FROM pg_database WHERE datname = '${dbName}'`;
      const result = await this.knex.raw(query);
      return !!result.rowCount;
    } catch (err) {
      throw err;
    } finally {
      this.destroyConnection();
    }
  }

  async createDatabase(dbName) {
    try {
      this.createConnection();
      const query = `CREATE DATABASE ${dbName}`;
      const result = await this.knex.raw(query);
      return !!result.rowCount;
    } catch (err) {
      throw err;
    } finally {
      this.destroyConnection();
    }
  }

  async dropDatabase(dbName) {
    try {
      this.createConnection();
      const query = `DROP DATABASE IF EXISTS ${dbName}`;
      const result = await this.knex.raw(query);
      return !!result.rowCount;
    } catch (err) {
      throw err;
    } finally {
      this.destroyConnection();
    }
  }
}

module.exports = DbCreator;