@eliware/mysql

A simple, dependency-injectable MySQL connection pool utility for Node.js, supporting both ESM and CommonJS.

Table of Contents

• Features
• Installation
• Usage
  • ESM Example
  • CommonJS Example
• API
• TypeScript
• License

Features

• Simple async function to create a MySQL connection pool
• Supports both ESM and CommonJS
• Dependency injection for testability (mock MySQL, logger, or env)
• TypeScript type definitions included
• Helpful error logging
• Supports optional pool config via environment variables

Installation

npm install @eliware/mysql

Usage

ESM Example

import { createDb } from '@eliware/mysql';

(async () => {
  const db = await createDb();
  // Use db.query, db.execute, etc.
  await db.end();
})();

CommonJS Example

const { createDb } = require('@eliware/mysql');

(async () => {
  const db = await createDb();
  // Use db.query, db.execute, etc.
  await db.end();
})();

API

createDb(options?)

Creates and returns a MySQL connection pool.

Parameters:

• options.env (object, optional): Environment variables (default: process.env)
• options.mysqlLib (object, optional): mysql2/promise module (default: static import/require, must have createPool)
• options.log (object, optional): Logger instance (default: @eliware/log)

Returns:

• Promise<Pool>: A MySQL connection pool instance

Throws:

• If required environment variables are missing
• If pool creation fails

Environment Variables:

Required:

• MYSQL_HOST - MySQL server host
• MYSQL_USER - MySQL username
• MYSQL_PASSWORD - MySQL password
• MYSQL_DATABASE - MySQL database name

Optional:

• MYSQL_WAIT_FOR_CONNECTIONS - true|false|1|0|yes|no|off (default: true)
• MYSQL_CONNECTION_LIMIT - Max connections in pool (default: 10)
• MYSQL_QUEUE_LIMIT - Max queued connection requests (default: 0)
• MYSQL_PORT - MySQL server port (default: 3306)

Example:

const db = await createDb({
  env: {
    MYSQL_HOST: 'localhost',
    MYSQL_USER: 'root',
    MYSQL_PASSWORD: 'password',
    MYSQL_DATABASE: 'test',
    MYSQL_PORT: '3306',
    MYSQL_WAIT_FOR_CONNECTIONS: 'true',
    MYSQL_CONNECTION_LIMIT: '20',
    MYSQL_QUEUE_LIMIT: '5',
  },
  mysqlLib: require('mysql2/promise'), // or import * as mysql2Promise from 'mysql2/promise' for ESM
  log: console,
});

TypeScript

Type definitions are included:

export interface CreateDbOptions {
  /** Environment variables (default: process.env) */
  env?: Record<string, string>;
  /** mysql2/promise module (default: static import/require, must have createPool) */
  mysqlLib?: any;
  /** Logger instance (default: log) */
  log?: any;
}

export function createDb(options?: CreateDbOptions): Promise<any>;

Support

For help, questions, or to chat with the author and community, visit:

eliware.org on Discord

License

MIT © 2025 Eli Sterling, eliware.org

Links

• Home Page
• GitHub
• npm
• Discord