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Using different Class Methods, depending on the used target compiler option

How can I tell TypeScript to use different-written methods (on the same class), depending on the used target option within the tsconfig.json file?
I'm currently re-writing one of my scripts into TypeScript to just "manage" one source, because at the moment I'm working with an ES5 and an ES6 file next to each other. Since TypeScript supports to just change the output target in the tsconfig.json file, I would just need one version to update and maintain.
The problem is I'm using a generator in the ES6 version, which theoretically shouldn't be this issue because TypeScript "adds" a pseudo generator to the top of my ES5 file. BUT: My Pseudo-Generator code, which I'm currently using on the ES5 file, is "cleaner" and way less code.
The Question
Is it possible to overwrite the respective "generator" method or using any special comment annotation (such as //#ts-target) to tell the compiler which code (function body) should be used depending on the used target in the configuration file? (Even If I couldn't found such solution on the official documentation).
An additional function or script, which can be added into the TypeScript compiler process would also help, I guess, because I'm compiling them using a small node.js script (which compiles both ES files without changing the tsconfig.json file directly.)
Or is there any kind of extension, to move different methods of the same class into different files? This way I could "extract" the respective "generator" methods, but this would cause another question: How can I link them depending on the target, because I'm using /// <reference /> linking on the main script file to get all together.
Any other idea?
class Option {
///#ts-target ES5
__walkerVariable1:any undefined
__walkerVariable2:any undefined
__walkerVariable3:any undefined
walker() {
/* Some Pseudo-Walker Code for ES5 */
}
///#ts-target ES6
*walker() {
/* Real Walker Code for ES6 */
}
}
Currently, a Pseudo-Generator code gets added in the ES5 version of my script. I want to prevent this by using a different method / function body with my own Pseudo-Generator. Therefore, I need to tell TypeScript that he should "ignore" the Pseudo-Generator in ES6 / the Real-Generator in ES5 and just render one of them depending on the used target option.

That was a bit tricky, but I found a solution thanks to this GitHub issue.
As mentioned above, I'm using my own node.js script to compile the TypeScript files into two different JavaScript versions (ES5 and ES6). Therefore, I'm using the TypeScript API with the ts.createProgram method. This method allows to add a host object as third parameter, which takes over some compiler processes and one of those is the file loader, called getSourceFile.
The rest is then relatively easy: Searching for a custom comment annotation (in my case \\\#ts-target:ES5 and \\\#ts-target:ES6 respectively) and filter them using RegExp. Maybe not the best solution, but it works!
function compileTS(){
let config = readConfig("ts/tsconfig.json");
let host = ts.createCompilerHost(config.options);
let sourceFile = host.getSourceFile;
// ES5 JavaScript
(function(config){
host.getSourceFile = function(filename) {
if(filename === "ts/options.ts"){
let file = fs.readFileSync("./ts/options.ts").toString();
file = file.replace(/[ ]+\/\/\/\#ts\-target\:ES6\s+([\s\S]*)\/\/\/\#ts\-target\:ES6/gm, "");
return ts.createSourceFile(filename, file, ts.ScriptTarget.ES5, true);
}
return sourceFile.call(host, filename);
}
let program = ts.createProgram(config.fileNames, config.options, host);
let emitResult = program.emit();
report(ts.getPreEmitDiagnostics(program).concat(emitResult.diagnostics));
if(emitResult.emitSkipped){
process.exit(1);
}
}(config));
// ES6 JavaScript
config.options.target = 2;
config.options.outFile = "../dist/js/tail.select-es6.js";
(function(config){
host.getSourceFile = function(filename) {
if(filename === "ts/options.ts"){
let file = fs.readFileSync("./ts/options.ts").toString();
file = file.replace(/[ ]+\/\/\/\#ts\-target\:ES5\s+([\s\S]*)\/\/\/\#ts\-target\:ES5/gm, "");
return ts.createSourceFile(filename, file, ts.ScriptTarget.ES2015, true);
}
return sourceFile.call(host, filename);
}
let program = ts.createProgram(config.fileNames, config.options, host);
let emitResult = program.emit();
report(ts.getPreEmitDiagnostics(program).concat(emitResult.diagnostics));
if(emitResult.emitSkipped){
process.exit(1);
}
}(config));
}

NodeJS: Single object with all requires, or "standard" paths in code?

So, I'm a big fan of creating global namespaces in javascript. For example, if my app is named Xyz I normally have an object XYZ which I fill with properties and nested objects, for an example:
XYZ.Resources.ErrorMessage // = "An error while making request, please try again"
XYZ.DAL.City // = { getAll: function() { ... }, getById: function(id) { .. } }
XYZ.ViewModels.City // = { .... }
XYZ.Models.City // = { .... }
I sort of picked this up while working on a project with Knockout, and I really like it because there are no wild references to some objects declare in god-knows-where. Everything is in one place.
Now. This is ok for front-end, however, I'm currently developing a basic skeleton for a project which will start in a month, and it uses Node.
What I wanted was, instead of all the requires in .js files, I'd have a single object ('XYZ') which would hold all requires in one place. For example:
Instead of:
// route.js file
var cityModel = require('./models/city');
var cityService = require('./services/city');
app.get('/city', function() { ...........});
I would make an object:
XYZ.Models.City = require('./models/city');
XYZ.DAL.City = require('./services/city');
And use it like:
// route.js file
var cityModel = XYZ.Models.City;
var cityService = XYZ.DAL.City;
app.get('/city', function() { ...........});
I don't really have in-depth knowledge but all of the requires get cached and are served, if cached, from memory so re-requiring in multiple files isn't a problem.
Is this an ok workflow, or should I just stick to the standard procedure of referencing dependencies?
edit: I forgot to say, would this sort-of-factory pattern block the main thread, or delay the starting of the server? I just need to know what are the downsides... I don't mind the requires in code, but I just renamed a single folder and had to go through five files to change the paths... Which is really inconvenient.

I think that's a bad idea, because you are going to serve a ton of modules every single time, and you may not need them always. Your namespaced object will get quite monstrous. require will check the module cache first, so I'd use standard requires for each request / script that you need on the server.

Getting name of a module in node.js

Does anyone know how to get the name of a module in node.js / javascript
so lets say you do
var RandomModule = require ("fs")
.
.
.
console.log (RandomModule.name)
// -> "fs"

If you are trying to trace your dependencies, you can try using require hooks.
Create a file called myRequireHook.js
var Module = require('module');
var originalRequire = Module.prototype.require;
Module.prototype.require = function(path) {
console.log('*** Importing lib ' + path + ' from module ' + this.filename);
return originalRequire(path);
};
This code will hook every require call and log it into your console.
Not exactly what you asked first, but maybe it helps you better.
And you need to call just once in your main .js file (the one you start with node main.js).
So in your main.js, you just do that:
require('./myRequireHook');
var fs = require('fs');
var myOtherModule = require('./myOtherModule');
It will trace require in your other modules as well.
This is the way transpilers like babel work. They hook every require call and transform your code before load.

I don't know why you would need that, but there is a way.
The module variable, which is loaded automatically in every node.js file, contains an array called children. This array contains every child module loaded by require in your current file.
This way, you need to strict compare your loaded reference with the cached object version in this array in order to discover which element of the array corresponds to your module.
Look this sample:
var pieces = require('../src/routes/headers');
var childModuleId = discoverChildModuleId(pieces, module);
console.log(childModuleId);
function discoverChildModuleId(object, moduleObj) {
"use strict";
var childModule = moduleObj.children.find(function(child) {
return object === child.exports;
});
return childModule && childModule.id;
}
This code will find the correspondence in children object and bring its id.
I put module as a parameter of my function so you can export it to a file. Otherwise, it would show you modules of where discoverChildModule function resides (if it is in the same file won't make any difference, but if exported it will).
Notes:
Module ids have the full path name. So don't expect finding ../src/routes/headers. You will find something like: /Users/david/git/...
My algorithm won't detect exported attributes like var Schema = require('mongoose').Schema. It is possible to make a function which is capable of this, but it will suffer many issues.

From within a module (doesn't work at the REPL) you can...
console.log( global.process.mainModule.filename );
And you'll get '/home/ubuntu/workspace/src/admin.js'

Collect multiple RequireJS dependencies

There's a set of JS modules representing similar OOP Classes: think of e.g. different types of backend tasks (SendEmailTask, WriteToDbTask, WriteToDiskTask), or different actions on a drawing canvas (DrawArc, DrawLine, DrawBezier). Those are just examples.
Each of those is a single JS file, with its own define, and they're all located in a common directory. In a client module that depends on all of those, the dependency list and argument list have to include each one of those separately, e.g. something like:
define([
'tasks/sendEmailTask', 'tasks/writeToDbTask', 'tasks/writeToDiskTask', ...
], function (SendEmailTask, WriteToDbTask, WriteToDiskTask, ...) {
/* ... */
/* ... new SendEmailTask(); */
/* ... new WriteToDbTask(); */
/* ... new WriteToDiskTask(); */
});
and they both must be updated everytime a new module is added to the set, e.g. MakeCoffeeTask, which seems to me as a BadThing™.
Is there a way to avoid those last issues? I was thinking of a couple of possible ways, but I don't know how to make them work:
Create a kind of namespace module. Each of those sub-modules depends on the namespace one and adds its definition to it. But than if the client too depends only on the namespace, how do you ensure that client gets loaded after all sub-modules?
Express both dependencies and arguments with some kind of wildcard, like 'tasks/*' for dependency and < no idea > for arguments.

You can make a different module for each section. For example: 'tasks/main'
in the Task main you can include all the files you need. and in the task main, all the function of task will be assigned. and you call high level functions. Take look :
define(['tasks/main'], function(task){
task.add('Project Status meeting');
task.SendEmailNotification('tAll');
});
in the task/main.js :
define(['tasks/sendEmailTask', 'tasks/writeToDbTask', 'tasks/writeToDiskTask',], function(sendEmailTask, writeToDbTask, writeToDiskTask){
var task = {
add = function(taskObj){
// write your code using writeToDbTask, writeToDiskTask
},
SendEmailNotification = function(whom){
// write your code using sendEmailTask, writeToDbTask, writeToDiskTask
};
return task;
});
does it help you ?

I was not able to find any other solution. This is what I came up with in the meantime... it is just an improvement over current situation, but I don't think it solves the posed issues.
// in tasks/taskNamespace.js or in any client code
define (function(require) {
var _taskArray = [
require('tasks/sendEmailTask'),
require('tasks/writeToDbTask'),
require('tasks/writeToDiskTask'),
/* ... , */
];
var TaskNamespace = {};
_taskArray.forEach(function (taskClass) {
TaskNamespace[taskClass.name] = taskClass;
});
return TaskNamespace;
});
It takes advantage of RequireJS Sugar syntax and of JS Function.name coming new feature, proposed in ES6.
What's the end result? You still have to manually add each Class to a list, but it's only one list instead of two. WHOA

NodeJS - How to reference function in one require() file from another require() file?

This is my second weekend playing with Node, so this is a bit newbie.
I have a js file full of common utilities that provide stuff that JavaScript doesn't. Severely clipped, it looks like this:
module.exports = {
Round: function(num, dec) {
return Math.round(num * Math.pow(10,dec)) / Math.pow(10,dec);
}
};
Many other custom code modules - also included via require() statements - need to call the utility functions. They make calls like this:
module.exports = {
Init: function(pie) {
// does lots of other stuff, but now needs to round a number
// using the custom rounding fn provided in the common util code
console.log(util.Round(pie, 2)); // ReferenceError: util is not defined
}
};
The node.js file that is actually run is very simple (well, for this example). It just require()'s in the code and kicks off the custom code's Init() fn, like this:
var util = require("./utilities.js");
var customCode = require("./programCode.js");
customCode.Init(Math.PI);
Well, this doesn't work, I get a "ReferenceError: util is not defined" coming from the customCode. I know everything in each required file is "private" and this is why the error is occuring, but I also know that the variable holding the utility code object has GOT to be stored somewhere, perhaps hanging off of global?
I searched through global but didn't see any reference to utils in there. I was thinking of using something like global.utils.Round in the custom code.
So the question is, given that the utility code could be referred to as anything really (var u, util, or utility), how in heck can I organize this so that other code modules can see these utilities?

There are at least two ways to solve this:
If you need something from another module in a file, just require it. That's the easy one.
Provide something which actually builds the module for you. I will explain this in a second.
However, your current approach won't work as the node.js module system doesn't provide globals as you might expect them from other languages. Except for the things exported with module.exports you get nothing from the required module, and the required module doesn't know anything of the requiree's environment.
Just require it
To avoid the gap mentioned above, you need to require the other module beforehand:
// -- file: ./programCode.js
var util = require(...);
module.exports = {
Init: function(pie) {
console.log(util.Round(pie, 2));
}
};
requires are cached, so don't think too much about performance at this point.
Keep it flexible
In this case you don't directly export the contents of your module. Instead, you provide a constructor that will create the actual content. This enables you to give some additional arguments, for example another version of your utility library:
// -- file: ./programCode.js
module.exports = {
create: function(util){
return {
Init: function(pie) {
console.log(util.Round(pie, 2));
}
}
}
};
// --- other file
var util = require(...);
var myModule = require('./module').create(util);
As you can see this will create a new object when you call create. As such it will consume more memory as the first approach. Thus I recommend you to just require() things.