Add esm exports

[brianc]

This builds off of #3407 and hopefully helps address the issue here.

[brianc]

Still adding more tests, but wanted to open the PR to see how it runs in CI.

edit: yay - tests are passing. now I'll add some more.

[cloudflare-workers-and-pages]

Deploying node-postgres with    Cloudflare Pages

Latest commit:	8162202
Status:	✅  Deploy successful!
Preview URL:	https://2ed736ef.node-postgres.pages.dev
Branch Preview URL:	https://bmc-add-esm-exports.node-postgres.pages.dev

View logs

[brianc]

todo:

• test if this gets fixed
• update documentation to ESM imports & put note about also supporting commonJS

[Copilot]

Pull Request Overview

This PR adds ECMAScript Module (ESM) export wrappers for several pg-related packages to improve compatibility with ESM environments. Key changes include:

• Creation of ESM wrapper files for pg-protocol, pg-pool, pg-native, pg-cursor, and pg-connection-string.
• Addition of test files to verify the ESM exports.
• Update of pg-cursor to use the pg module for retrieving Result and utils.

Reviewed Changes

Copilot reviewed 21 out of 28 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
packages/pg-protocol/esm/index.js	Adds ESM exports for pg-protocol re-exporting from the dist build
packages/pg-pool/esm/index.mjs	Provides an ESM wrapper for pg-pool with default export
packages/pg-native/esm/index.mjs	Provides an ESM wrapper for pg-native with default export
packages/pg-esm-test/pg.test.js	Introduces tests for exported Client, Pool, and default export from pg
packages/pg-esm-test/pg-query-stream.test.js	Verifies the default export for pg-query-stream
packages/pg-esm-test/pg-pool.test.js	Validates the Pool constructor export for pg-pool
packages/pg-esm-test/pg-native.test.js	Validates the Client constructor export for pg-native
packages/pg-esm-test/pg-cursor.test.js	Verifies the default export for pg-cursor
packages/pg-esm-test/pg-connection-string.test.js	Confirms the parsing functions export from pg-connection-string
packages/pg-esm-test/pg-cloudflare.test.js	Tests the CloudflareSocket export, though the test description mismatches
packages/pg-cursor/index.js	Refactors pg-cursor to import Result and utils from the pg module
packages/pg-cursor/esm/index.mjs	Provides an ESM wrapper for pg-cursor with default export
packages/pg-connection-string/esm/index.mjs	Exposes the parse, toClientConfig, and parseIntoClientConfig functions via ESM

Files not reviewed (7)

• package.json: Language not supported
• packages/pg-cloudflare/package.json: Language not supported
• packages/pg-connection-string/package.json: Language not supported
• packages/pg-cursor/package.json: Language not supported
• packages/pg-esm-test/package.json: Language not supported
• packages/pg-native/package.json: Language not supported
• packages/pg-pool/package.json: Language not supported

Comments suppressed due to low confidence (1)

packages/pg-esm-test/pg-cloudflare.test.js:5

• The test description 'pg-pool' does not match the Cloudflare context; consider renaming it to 'pg-cloudflare' for clarity.

describe('pg-pool', () => {

[B4nan]

This feels breaking, since now you are disallowing the imports for pg/lib/type-overrides. Or is there some other way to do this import?

import TypeOverrides from 'pg/lib/type-overrides';

[mesqueeb]

@B4nan importing from undocumented paths is debatable wether it's breaking or not.

To my understanding, in an ESM environment this (your snippet) will get tricky since the source code is mostly CJS, and ESM only has single wrapper index files.

[B4nan]

Fair enough, but how can we do this properly if this was the wrong way? i believe that class is supposed to be used in downstream.

[mesqueeb]

@B4nan I guess the best way is to make sure that class is also exported as part of the esm-facing index file.
So that you can do:
import { TypeOverrides } from 'pg'
That should be a simple addition if this isn't already the case.

[B4nan]

Btw I learned about this trick ages ago from this issue, maybe there is another way to override type mapping per connection?

#1838

There is an old PR that was exposing the class in root exports but it never got merged.

#2369

[mesqueeb]

@B4nan I did what i could by adding a voice: #2369 (comment)