Script Node.js from C# in vscode - Edge.js - Unexpected token

Question

I successfully used vs code to write the sample program to script Node.js from C#. I use the following code block directly from https://github.com/tjanczuk/edge:

using System;
using System.Threading.Tasks;
using EdgeJs;

class Program
{
    public static async Task Start()
    {
        var func = Edge.Func(@"
            return function (data, callback) {
                callback(null, 'Node.js welcomes ' + data);
            }
        ");

        Console.WriteLine(await func(".NET"));
    }

    static void Main(string[] args)
    {
        Start().Wait();
    }
}

The above is working successfully with .NET Framework 4.5.2 and 4.8.0

Also, I successfully wrote a program in Node.js to invoke a GET request using Newman:

const newman = require('newman'); // require newman in your project
const theCollec = '.\\collections\\vs code test.postman_collection.json';
//call newman.run to pass `options` object and wait for callback
newman.run({
   collection: require(theCollec),
   reporters: 'cli'
}, function (err) {
   if (err) { throw err; }
   console.log('collection run complete!');
});

Now, I am trying to include the Newman code block in the C# program, but it is not working. I am getting the following errors when I run the program using dotnet run:

using System;
using System.Threading.Tasks;
using EdgeJs;

namespace TestNodeJSNET
{

    class Program
    {
        public static async Task Start()
        {
            var func = Edge.Func(@"
                var newman = require('newman'); // require newman in your project
                const examples = require('.\\..\\examples.js');
                return function (data, callback) {
                    // var WebSocketServer = require('ws').Server;
                    const theCollec = '.\\..\\collections\\Postman Echo.postman_collection.json';
                    // call newman.run to pass `options` object and wait for callback
                    newman.run({
                       collection: require(theCollec),
                       reporters: 'cli'
                    }, function (err) {
                        console.log('This is the function part of Newman.');
                        console.log(err);
                       if (err) { throw err; }
                       callback(null, 'Node.js welcomes ' + data + ' - ' + theCollec + ' - examples hi :' + examples.say());
                       console.log('collection run complete!');
                    });
                    console.log('This is from NodeJS in .NET');
                    // callback(null, 'Node.js welcomes ' + data + ' - ' + theCollec + ' - examples hi :' + examples.say());
                }
            ");

            Console.WriteLine(await func(".NET"));
        }

        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
            Console.WriteLine("Hello World 3!");
            Start().Wait();
        }
    }
}

I am getting the following errors:

Unhandled Exception: System.AggregateException: One or more errors occurred. ---> System.Exception: C:\Projects\TestNodeJSNET\node_modules\ws\lib\websocket.js:460
      ...options
      ^^^

SyntaxError: Unexpected token ...
    at createScript (vm.js:74:10)
    at Object.runInThisContext (vm.js:116:10)
    at Module._compile (module.js:533:28)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:503:32)
    at tryModuleLoad (module.js:466:12)
    at Function.Module._load (module.js:458:3)
    at Module.require (module.js:513:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (C:\Projects\TestNodeJSNET\node_modules\ws\index.js:3:19)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at TestNodeJSNET.Program.<Start>d__0.MoveNext()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at System.Threading.Tasks.Task.Wait()
   at TestNodeJSNET.Program.Main(String[] args)

See the snapshot below of the code that caused the error.

I appreciate your help to resolve this issue.

---

Update 1

I confirmed that the problem is from the NuGet Edge.js. I used NPM newman version 4.6.1 and the problem is resolved. I used an example package with the spread operator and used outside Edge.js and inside, and the problem triggered only within Edge.js from C#.

Following is the examples.js module I used to pinpoint the root cause of the issue:

console.log("evaluating example.js");

var invisible = function () {
  console.log("invisible");
}

exports.message = "hi";
exports.arr = [1,2,3,4,5];
exports.obj = {name:"Tarek", subject:"Math"};

exports.say = function () {
  console.log(exports.message);
  console.log("Testing the spread operator for arr: ", ...exports.arr);
  //var obj2 = {...exports.obj};
  var obj2 = {key:"Obj 2", val:"val of obj2"};
  console.log("Testing the spread operator for obj: ", obj2);
  return "Competed log of " + exports.message;
}

Now, I can live with that solution, but I’d like to do more.

I can transpile the Newman Module and all its dependencies to a lower version using Babel. I did some research, and most probably it will work, but still not clear how to do that. I need to do more research.

However, the only issue with using Babel is how to make it a reliable solution. This means I need to set up my project in such a way that it will install Newman’s latest version using npm install newman then trigger the Babel transpiler to compile the modules to a lower version using minimal manual interventions, and yet, still be able to use the node API require("newman"). I still didn’t figure out how to wrap my head around this issue.

I think we need to create a task using vs code or script build in package.json to call Babel transpiler to compile the Newman code in the node_module folder and create the output in say node_module_dist or something like that. How is that possible?

I am looking for help to implement the transpiler option using Babel or with any other alternative.

---

Update 2:

I managed to set up Babel and used the following babel.config.js:

module.exports = function (api) {
  api.cache(true);

  const presets = [
    // "@babel/preset-env",
    // ['@babel/preset-env', {targets: {node: 'current'}}],
    ['@babel/preset-env', { targets: { node: 'current' }, modules: "auto" }],
    "@babel/preset-typescript",
    ['@babel/preset-react', { targets: { node: 'current' } }],
    // ['es2015', {modules: false}]
  ];
  const plugins = [
    "@babel/plugin-transform-typescript", "@babel/plugin-syntax-jsx",
    "@babel/plugin-transform-strict-mode",
    ["@babel/plugin-transform-modules-commonjs", {
      "strictMode": false
    }]
  ];
  const include =
    ["node_modules/postman-collection/lib/collection/item.js",
      "node_modules/csv-parse/lib/index.js",
      "node_modules/mkdirp/lib/opts-arg.js",
      "node_modules/newman/lib/node-version-check/index.js",
      "./node_modules/@babel/helper-define-polyfill-provider/src/browser/dependencies.js",
      ".\\node_modules\\@babel\\helper-define-polyfill-provider\\src\\node\\dependencies.js",
      ".\\node_modules\\@babel\\plugin-syntax-typescript\\test\\fixtures\\disallow-jsx-ambiguity\\type-parameter-unambiguous\\output.js",
      ".\\node_modules\\has-symbols\\test\\shams\\core-js.js",
      ".\\node_modules\\has-symbols\\test\\shams\\get-own-property-symbols.js",
      ".\\node_modules\\postman-sandbox\\lib\\sandbox\\index.js",
    ];
  const exclude = [
  ];
  return {
    presets,
    plugins,
    include,
    exclude,
    parserOpts: { allowReturnOutsideFunction: true },
    generatorOpts: { compact: true }
  };
}

I am using this command to transpile the node_modules under the sub-folder required_modules of the project root, and the output is 'node_module_dist':

cd required_modules
npx babel .\node_modules\ --out-dir .\node_modules_dist\

This setup is actually working and did transpile about 20 JavaScript files to remove the JavaScript features not working because of Edge.js.

However, the final error I got which I cannot resolve using any bable preset or plugin:

SyntaxError: C:\Projects\TestNodeJSNET\required_modules\node_modules\postman-sandbox\lib\sandbox\index.js: Deleting local variable in strict mode. (73:20)

  71 | // We don't need direct access to the global bridge once it's part of execution closure.
  72 | // eslint-disable-next-line no-global-assign, no-implicit-globals, no-delete-var
> 73 | bridge = undefined; delete bridge;
     |                     ^
  74 |
    at instantiate (C:\Projects\TestNodeJSNET\node_modules\@babel\parser\lib\index.js:72:32)
    at constructor (C:\Projects\TestNodeJSNET\node_modules\@babel\parser\lib\index.js:358:12)
    at Object.raise (C:\Projects\TestNodeJSNET\node_modules\@babel\parser\lib\index.js:3335:19)
    at Object.parseMaybeUnary (C:\Projects\TestNodeJSNET\node_modules\@babel\parser\lib\index.js:12474:16)
    at Object.parseMaybeUnary (C:\Projects\TestNodeJSNET\node_modules\@babel\parser\lib\index.js:10708:20)
    at Object.parseMaybeUnaryOrPrivate (C:\Projects\TestNodeJSNET\node_modules\@babel\parser\lib\index.js:12284:61)
    at Object.parseExprOps (C:\Projects\TestNodeJSNET\node_modules\@babel\parser\lib\index.js:12291:23)
    at Object.parseMaybeConditional (C:\Projects\TestNodeJSNET\node_modules\@babel\parser\lib\index.js:12261:23)
    at Object.parseMaybeAssign (C:\Projects\TestNodeJSNET\node_modules\@babel\parser\lib\index.js:12214:21)
    at Object.parseMaybeAssign (C:\Projects\TestNodeJSNET\node_modules\@babel\parser\lib\index.js:10631:20) {
  code: 'BABEL_PARSE_ERROR',
  reasonCode: 'StrictDelete',
  loc: Position { line: 73, column: 20, index: 3644 },
  pos: [Getter/Setter]  

I am not sure if this is the right path, and I really appreciate your help. It seems that Babel is unable to transpile this feature Deleting local variable in strict mode and may encounter many more issues.