.d.ts typescript definition doesn't match js with proto3 optional fields

[mattnathan]

Given a proto file like

syntax = "proto3";

message MyMessage {
  optional float my_prop = 1;
}

Running the generator with options --js_out=import_style=commonjs,binary:. --grpc-web_out=import_style=commonjs+dts,mode=grpcwebtext:. the generated _pb.js file correctly has the get, set, has, and clear methods for interacting with the property. The _pb.d.ts file, however, describes the property using the fallback enum representation with get, set, and a MyPropCase enum for describing the _NOT_SET and set semantics.

While I understand that this is technically correct for a language generator to describe the proto message in this way (that's how backwards compatibility is supported), this doesn't really work in this case as the .d.ts file is supposed to describe the .js file.

Anyway, sorry if this is reported elsewhere, I couldn't find anything when searching.

[mattnathan]

I have created a PR.

I'm no C/C++ developer so I hope the change is correct. I'm also a little lost for how to build and/or test the change.
I want to help, but will need pointers from someone who knows this project a little more that I do.

[sampajano]

@mattnathan Thanks so much again for raising the issue and creating a PR! It's a great issue to fix! 😃😃