verify-mssql-connection.js

import { Connection } from 'tedious';

class TediousClient {
  constructor(config) {
    this.config = config;
    this._cx = null;
  }

  connect() {
    if (!this._cx) {
      console.log('Connecting to', this.config.server, '...');
      this._cx = new Promise((resolve, reject) => {
        const db = new Connection(this.config);
        db.on('connect', (err) => err
                ? reject(err)
                : resolve(db));
      });
    }
    return this._cx;
  }
}

async function verifyConnection(client) {
  try {
    const db = await client.connect();
    console.log('Connected!');
  } catch (err) {
    console.warn(err);
  }
}

const client = new TediousClient({
  userName: process.env.DATABASE_USER,
  password: process.env.DATABASE_PASSWORD,
  server: process.env.DATABASE_URL,
  database: process.env.DATABASE_NAME
});

verifyConnection(client);