Basic async/await question in Next

Unanswered

Virginia's Warbler posted this in #help-forum

Virginia's WarblerOP

2024-05-25T13:05:28.015Z

This might be a primary school question, but:

Because of this await, there obviously needs to be an async: https://github.com/Ruslan-Aliyev/Next-Tailwind-Typescript/blob/master/src/app/_utils/db.ts#L3
But, how can I include a async here?

Also, when I run npm run dev, no error happens and all continues well. The error only happens when I run npm run build. Why is that?

6 Replies

Brown bear

2024-05-25T13:36:35.553Z

create an async arrow function that will return the logic.

const db = async () => {
    await mysql.createConnection({
        host: process.env.DB_HOST,
        user: process.env.DB_USER,
        password: process.env.DB_PASS,
        database: process.env.DB_NAME,
    })
}

or you can wrap entire logic into an async function

const connectDB = async () => {
    const db = await mysql.createConnection({
        host: process.env.DB_HOST,
        user: process.env.DB_USER,
        password: process.env.DB_PASS,
        database: process.env.DB_NAME,
    });
    db.on('error', (err) => {
        console.log('- STATS Mysql2 connection died:', err);
    });
}

@Brown bear or you can wrap entire logic into an async function `const connectDB = async () => { const db = await mysql.createConnection({ host: process.env.DB_HOST, user: process.env.DB_USER, password: process.env.DB_PASS, database: process.env.DB_NAME, }); db.on('error', (err) => { console.log('- STATS Mysql2 connection died:', err); }); }`

Virginia's WarblerOP

2024-05-25T14:29:28.686Z

But, if I write this way, then how can I export and import db?

I tried writing this way, then export default connectDB;
And when I imported it, I wrote import {db} from "../_utils/db.ts"; instead of import db from "../_utils/db.ts";, but that didnt work

Brown bear

2024-05-25T14:32:20.793Z

that's because you've exported the function as a default export.

American Crow

2024-05-25T14:41:24.100Z

// db.js

const mysql = require('mysql2/promise');

export async function initializeDatabase() {
  const db = await mysql.createConnection({
    host: process.env.DB_HOST,
    user: process.env.DB_USER,
    password: process.env.DB_PASS,
    database: process.env.DB_NAME,
  });

  db.on('error', (err) => {
    console.log('- STATS Mysql2 connection died:', err);
  });

  return db;
}

// Usage in another file
import { initializeDatabase } from './db';

async function someFunction() {
  const db = await initializeDatabase();
  // Use the db connection
}