regression 1.0.16: not possible to use in ESM build and nodejs

[tripodsan]

the change in bc5adb8 gives the following error in esm builds:

import { AwsV4Signer } from 'aws4fetch';
...

file:///Users/nobody/codez/test/src/utils.js:18
import { AwsV4Signer } from 'aws4fetch';
         ^^^^^^^^^^^
SyntaxError: Named export 'AwsV4Signer' not found. The requested module 'aws4fetch' 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 'aws4fetch';
const { AwsV4Signer } = pkg;

changing it to the CJS format produces:

import aws4fetch from 'aws4fetch';
const { AwsV4Signer } = aws4fetch;

(node:63327) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.
(Use `node --trace-warnings ...` to show where the warning was created)

/Users/nobody/codez/test/node_modules/aws4fetch/dist/aws4fetch.esm.js:279
export { AwsClient, AwsV4Signer };
^^^^^^

SyntaxError: Unexpected token 'export'

---

Renaming the ems files to .mjs solves the issue:

  "exports": {
    ".": {
      "import": "./dist/aws4fetch.esm.mjs",
      "worker": "./dist/aws4fetch.esm.mjs",
      "browser": "./dist/aws4fetch.umd.js",
      "require": "./dist/aws4fetch.cjs.js",
      "default": "./dist/aws4fetch.umd.js"
    }
  },

[mhart]

esm builds using what tool? It seems to work fine in esbuild

[mhart]

(also import aws4fetch from 'aws4fetch' is not CJS – CJS uses require)

[tripodsan]

esm builds using what tool? It seems to work fine in esbuild

just pure node 16

[tripodsan]

(also import aws4fetch from 'aws4fetch' is not CJS – CJS uses require)

yes. but this is the problem. node thinks that the ./dist/aws4fetch.esm.js is a CJS module, which it isn't.

[tripodsan]

minimal project: https://github.com/tripodsan/aws4fetch-test

$ node -v
v16.17.0

$ node index.js
file:///Users/nobody/codez/foo/index.js:1
import { AwsV4Signer } from 'aws4fetch';
         ^^^^^^^^^^^
SyntaxError: Named export 'AwsV4Signer' not found. The requested module 'aws4fetch' 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 'aws4fetch';
const { AwsV4Signer } = pkg;

[mhart]

Oh interesting – I didn't know anyone was using this directly from Node.js with ESM. When I first created this, Node.js didn't have fetch support, so importing from Node.js as an ESM module wasn't even a consideration.

I'll need to look into the best way to do this. There's the main/module/browser declarations at the top level of package.json and then all the exports declarations as well.

Best option might just be to have an mjs and a js version (for backwards compat)

[mhart]

Try out 1.0.17 and let me know how it goes

[tripodsan]

Try out 1.0.17 and let me know how it goes

perfect. works!

thanks for the quick turnaround