Execute javascript code from ASP.NET Core back-end using NodeServices

just read this article file:///E:/download/Execute%20javascript%20code%20from%20ASP.NET%20Core%20back-end%20using%20NodeServices%20good.htm

var _ = require('lodash');module.exports = {sortBy: function (callback, data, option) {var result = _.sortBy(data, [option]);
        callback(null, result);
    }
};

[Produces("application/json")]
[Route("api/Users")]publicclassUsersController : Controller
{
    [HttpGet("GetSortedUsers")]publicasync Task<IActionResult> SortedUsers([FromServices] INodeServices nodeServices, string sortBy){var data = new User[]
        {new User {Name = "fred", Age = 48},new User {Name = "barney", Age = 36},new User {Name = "fred", Age = 40},new User {Name = "barney", Age = 34}
        };var sortedUsers = await nodeServices.InvokeExportAsync<User[]>("./Node/lodash", "sortBy", data, sortBy);return Ok(sortedUsers);
    }
}

specially see this line var sortedUsers = await nodeServices.InvokeExportAsync<User[]>("./Node/lodash", "sortBy", data, sortBy);

this area is not clear ("./Node/lodash", "sortBy", data, sortBy);

first one is the js file path? second one is function name ? what is 3rd and 4th argument?

module.exports = function (callback, first, second) {
var result = first + second;
callback(/* error */ null, result);
};

var result = await nodeServices.InvokeAsync<int>("./addNumbers", 1, 2);

see this ("./addNumbers", 1, 2);

what is the name of js function ?

what this line callback(/* error */ null, result); will do?

please help me to understand how the above code will work. thanks