Gotcha with Generated Files and Clients

#grpc #node #protoc

When using [grpc-tools](https://www.npmjs.com/package/grpc-tools) to create generated Node.js files, you have three options the --grpc_out flag:

grpc_js: Generates code with require('@grpc/grpc-js') instead of require('grpc')

generate_package_definition: Generates code that does not require any gRPC library, and instead generates PackageDefinition objects that can be passed to the loadPackageDefinition function provided by both the grpc and @grpc/grpc-js libraries.

no option: Generates code with require('grpc')

Using the grpc_js or no option actually triggers protoc to create a generic client in the *_grpc_pb.js file:

exports.RouteGuideClient = grpc.makeGenericClientConstructor(RouteGuideService);

What I found was that you need to use the same instance of gRPC (not just the same version) for them to work together. This will not be a problem if you are declaring you protos, generated files, and clients all in the same project. However, I have mine spread in different npm packages, so I did not use this functionality.