feat: restore main field of package.json for environments that do not support exports field

[morishin]

I tried to use graphql-request for a ReactNative app. But build errors occured because metro bundler unfortunately does not support exports field yet...
So I would like to restore main field which was dropped by facebook/metro#670.
This change would only restore backward compatibility and would not have any bad effect on modern environments.

[jasonkuhrt]

Can you please update the docs about this topic. Just remove them. Also please make a new issue to remove main once the Metro issue is closed. Thanks!

[morishin]

I missed the workaround in the README! (sorry 💦 )
I tried the workaround, however, the following errors are still appearing.

So I would like this PR to be merged for fixing the errors. I will update the docs and make the new issue.

Metro has encountered an error: While trying to resolve module `graphql-request` from file `/app/lib/graphql/useGraphQL.ts`, the package `/app/node_modules/graphql-request/package.json` was successfully found. However, this package itself specifies a `main` module field that could not be resolved (`/app/node_modules/graphql-request/index`. Indeed, none of these files exist:

  * /app/node_modules/graphql-request/index(.native|.ios.ts|.native.ts|.ts|.ios.tsx|.native.tsx|.tsx|.ios.js|.native.js|.js|.ios.jsx|.native.jsx|.jsx|.ios.json|.native.json|.json)
  * /app/node_modules/graphql-request/index/index(.native|.ios.ts|.native.ts|.ts|.ios.tsx|.native.tsx|.tsx|.ios.js|.native.js|.js|.ios.jsx|.native.jsx|.jsx|.ios.json|.native.json|.json): /app/node_modules/metro/src/node-haste/DependencyGraph.js (283:17)

  281 |         }
  282 |         if (error instanceof InvalidPackageError) {
> 283 |           throw new PackageResolutionError({
      |                 ^
  284 |             packageError: error,
  285 |             originModulePath: from,
  286 |             targetModuleName: to,

ABI48_0_0RCTFatal
__37-[ABI48_0_0RCTCxxBridge handleError:]_block_invoke
_dispatch_call_block_and_release
_dispatch_client_callout
_dispatch_main_queue_drain
_dispatch_main_queue_callback_4CF
__CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__
__CFRunLoopRun
CFRunLoopRunSpecific
GSEventRunModal
-[UIApplication _run]
UIApplicationMain
main
start_sim
0x0

[jasonkuhrt]

@morishin ok thanks

[ismay]

Can you please update the docs about this topic. Just remove them. Also please make a new issue to remove main once the Metro issue is closed. Thanks!

Would it be possible to expand that to current tooling that is still using main? I'm still waiting on the resolve package to add support for parsing exports for example.

[jasonkuhrt]

@ismay yep please create that issue or chime into existing one if there, thanks!