We had a bug report against Remix: remix-run/remix#6665

When polyfilling tty, I get the following error:

TypeError: Cannot assign to read only property 'ReadStream' of object '[object Object]'

        module.exports[k5] = polyfill[k5];
                       ^

After some digging, I discovered that this is because the JSPM polyfill for tty looks like this:

// ...
var m = /*#__PURE__*/Object.freeze({
  __proto__: null,
  isatty: isatty,
  ReadStream: ReadStream,
  WriteStream: WriteStream
});

export { ReadStream, WriteStream, m as default, isatty };

The default export is a read-only object since it's been passed to Object.freeze, and then the code injected by this plugin attempts to mutate it:

module.exports = polyfill.default
for (let k in polyfill) {
  module.exports[k] = polyfill[k]
}

I initially tried to fix the injected CommonJS code by using Object.assign({}, polyfill.default, polyfill), but unless I'm missing something, I found that esbuild is able to handle export * even when imported from a CommonJS file. Using ES modules to handle the re-export seems a lot cleaner since it avoids these sorts of issues entirely, otherwise we'd need to handle all sorts of edge cases when re-exporting.

Status and versioning classification:

• Code changes have been tested and working fine, or there are no code changes