03 Load the proto

Both the server and client need the gRPC bindings derived from greeter.proto. Extract that work into a shared load.js:

// load.js
const protoLoader = require("@grpc/proto-loader");
const grpc = require("@grpc/grpc-js");

const packageDefinition = protoLoader.loadSync("greeter.proto");
const proto = grpc.loadPackageDefinition(packageDefinition).greeter;

module.exports = { grpc, proto };

What happens here:

1. protoLoader.loadSync reads greeter.proto from disk and parses it into a plain JS object (no code generation).
2. grpc.loadPackageDefinition wraps that object with the gRPC runtime, giving you service constructors and service descriptors.
3. .greeter selects the package greeter namespace — matching the package declaration in the proto file.
4. proto.Greeter is now a client constructor; proto.Greeter.service is the service descriptor used by the server.

Checkpoint — run this in your project directory (with greeter.proto present):

node -e "console.log(!!require('./load').proto.Greeter)"

Expected output:

true

If you see false or an error, check that greeter.proto is in the same directory as load.js.

Next: 04 The server