support esm

[its-dibo]

when running this package inside an ESM project, I got this error

import { Pool } from 'pg';
         ^^^^
SyntaxError: Named export 'Pool' not found. The requested module 'pg' is a CommonJS module, which may not support all module.exports as named exports.
CommonJS modules can always be imported via the default export, for example using:

import pkg from 'pg';
const { Pool } = pkg;

    at ModuleJob._instantiate (node:internal/modules/esm/module_job:124:21)
    at async ModuleJob.run (node:internal/modules/esm/module_job:190:5)

using the suggested form import pkg from 'pg'; disables the tree-shaking

[brianc]

fwiw there is very, very little (if any) code that would be removed with tree-shaking if you are importing the pool. It literally depends on all the code in the project.

[rubiagatra]

is the documentation wrong? @brianc https://node-postgres.com/

import { Client } from 'pg'
const client = new Client()
await client.connect()
 
const res = await client.query('SELECT $1::text as message', ['Hello world!'])
console.log(res.rows[0].message) // Hello world!
await client.end()

[brianc]

I'm open to a pull request to add ESM support so long as it maintains backwards compatibility.

[rubiagatra]

I will take a look @brianc maybe in this weekend

[aegatlin]

Hello, and thank you for the library @brainc <3

I got to this issue because the docs imply this type of import is supported here: https://node-postgres.com/apis/pool

import { Pool } from 'pg'
 
const pool = new Pool({
  host: 'localhost',
  user: 'database-user',
  max: 20,
  idleTimeoutMillis: 30000,
  connectionTimeoutMillis: 2000,
})

Should the docs be updated to the following?

import pg from 'pg'
 
const pool = new pg.Pool({
  host: 'localhost',
  user: 'database-user',
  max: 20,
  idleTimeoutMillis: 30000,
  connectionTimeoutMillis: 2000,
})

[its-dibo]

I'm open to a pull request to add ESM support so long as it maintains backwards compatibility.

nice <3

[mahnunchik]

Why is the documentation written in a way that clearly doesn’t work?

[nezi311]

FFS 07.2024 and the docs are stil not changed.

[brianc]

are the docs inaccurate? If so it would be helpful if you would point out where. I went through a while ago and tried to make them all clear and correct. You could also do a PR with the changes if that's easier.

[mesqueeb]

@brianc you might not have experienced issues if your projects build to commonJS, or you do build to ESM but you bundle the entire pg library.

IF you try to run the project in ESM without a bundler converting your source code, this runtime error will happen.

It's verifiable here as well:
https://arethetypeswrong.github.io/?p=pg%408.14.1

The docs are inaccurate in that when running in an ESM environment, named imports of Pg won't work.
Only this would work:

import pkg from 'pg';
const { Pool } = pkg;

the solution is that you define an exports field in your package.json. This will make your package available for both CJS and ESM environments. This can be done without other source code changes.

I could open a PR to do so if you agree with this solution. What do you think?