const serializer = require('proto3-json-serializer');

const root = protobuf.loadSync('test.proto');
const Type = root.lookupType('test.Message');
const message = Type.fromObject({...});

const serialized = serializer.toProto3JSON(message);

const root = protobuf.loadSync('test.proto');
const Type = root.lookupType('test.Message');
const json = {...};

const deserialized = serializer.fromProto3JSON(Type, json);

const assert = require('assert');
const path = require('path');
const protobuf = require('protobufjs');
const serializer = require('proto3-json-serializer');

// We'll take sample protos from google-proto-files but the code will work with any protos
const protos = require('google-proto-files');

// Load some proto file
const rpcProtos = protos.getProtoPath('rpc');
const root = protobuf.loadSync([
    path.join(rpcProtos, 'status.proto'),
    path.join(rpcProtos, 'error_details.proto'),
]);
const Status = root.lookupType('google.rpc.Status');

// If you have a protobuf object that follows proto3 JSON syntax
// https://developers.google.com/protocol-buffers/docs/proto3#json
// (this is an example of google.rpc.Status message in JSON)
const json = {
    code: 3,
    message: 'Test error message',
    details: [
        {
            '@type': 'google.rpc.BadRequest',
            fieldViolations: [
                {
                    field: 'field',
                    description: 'must not be null',
                },
            ],
        },
    ],
};

// You can deserialize it into a protobuf.js object:
const deserialized = serializer.fromProto3JSON(Status, json);
console.log(deserialized);

// And serialize it back
const serialized = serializer.toProto3JSON(deserialized);
assert.deepStrictEqual(serialized, json);