Explaining JavaScript and this to people.

[Jeremy Falcon]

:-D

Jeremy Falcon

[Jeremy Falcon]

Marc Clifton wrote:

You're off by 50 years. :) And this is exactly why Javascript is so hard to learn. There are no (and no good) resources for how to do things other than SO, CP, and dubious forums by 3rd party vendors. Why? Because who the heck is going to write a book on how to do X when, given the multi-dimensional landscape of web development, describing where X is in this trans-dimensional space is pretty much impossible.

You're absolutely right about that. One of the pain points I have with React learning is simply finding good resources on it. And to top it off, once you find one, it's out-of-date. And to top it off even more, it's not exactly places teach you production ready stuff. It's a royal PITA. The web really is a hodgepodge of kiddie playground crap where nobody wants to agree on anything. About the only reason I was able to even start making any sense of all this crap was a couple years back I pestered a coworker of mine for literally like a year asking him tons of questions.

Marc Clifton wrote:

Granted, all my examples are related to using jQuery and 3rd party frameworks, but it's impossible to disentangle Javascript from those things when doing web development.

Yeah totally. It is getting better at least, but the web is slow to migrate to new stuff. Being so popular and all there's a lot of existing crap to change before we make way for the new crap. And of course, by that time the new crap will be out-dated. :-D

Marc Clifton wrote:

The content of the tree (a jqxwidget) is programatically generated and I haven't figured out a simpler way of getting the text (not to mention the freaking ID) of the parent for a selected node.

Having never used that lib, you'd think they'd expose that somehow. Go figure.

Marc Clifton wrote:

And heaven help me if I have to learn one of the Angular/React/etc/ frameworks that jqwidgets claims to support. More obfuscation on top of nebulous indirection.

But... but... React! :-D

Marc Clifton wrote:

Yup -- I'm an old fart.

At least you can laugh about it. You reach an age where it's ok to laugh at stuff. That's called maturity. And I'd say I'm 39 so I understand, but I'm sure you'd call me a youngin'. :~

Jeremy Falcon

[Lost User]

Yeah I see just the feature of undefined behavior (in case you are familiar with this term) is a bad feature of those languages IMHO.

[Tomz_KV]

I tried JSFiddle and it worked. However, when I copied the exact code to a new HTML page, it behaved the same way as it was without "Orange". Here is the complete HTML code:

//copied from JSFiddle
    var fruit = 'Orange';
    window.fruit = 'Apple';

    // unlike other languages, in JavaScript we can invoke this in more ways than one
    function explainThis() {
        alert(fruit + ' ' + this.fruit);
    }

    explainThis(); // shows Orange Apple
    var stuff = new explainThis(); // shows Orange undefined

TOMZ_KV

[Tomz_KV]

Chrome 62.0.3202.94 and IE 11.726.15063.0

TOMZ_KV

[Jeremy Falcon]

Gotcha. It's because stuff ran on JSFiddle is a mock root and not the real root. When using the real root, as in your case, window is the default object, so in the real global scope the first two lines are pretty much the same since window is the default object and so the second assignment overwrites the first. In my original code, it was a fake root so to speak. I probably should've tested it first, but hey where's the fun in that. :) To illustrate...

// this is the real root in the global space
var fruitRoot = 'Banana'; // these two lines do the same thing
window.fruitRoot = 'Pineapple'; // this overwrites the previous line

  function explainThisRoot() {
     alert(fruitRoot + ' ' + this.fruitRoot);
  }

  explainThisRoot(); // shows Pineapple Pineapple
  var stuffRoot = new explainThisRoot(); // shows Pineapple undefined

  // this is an IIFE, simply put it's like a namespace
  (function () {
     // this can be thought of as a fake root, JSFiddle will do something similar to
     // constrain the user and prevent them from messing around with the entire page

     var fruit = 'Orange'; // not in the global space anymore so this isn't window
     window.fruit = 'Apple';

     // unlike other languages, in JavaScript we can invoke this in more ways than one
     function explainThis() {
        alert(fruit + ' ' + this.fruit);
     }

     explainThis(); // shows Orange Apple
     var stuff = new explainThis(); // shows Orange undefined
  })();

Jeremy Falcon

[Tomz_KV]

That explains it. :thumbsup:

TOMZ_KV

[Marc Clifton]

Jeremy Falcon wrote:

You reach an age where it's ok to laugh at stuff.

Yeah, works well with one's partner too. ;) At the end of the day, I end up treating these technologies like everything else, even C#/.NET: 1) Figure out how to do stuff the hard way 2) Look at how to make it easier and learn from others 3) Create a toolbox that mitigates some of the pain points 4) Liberally sprinkle code with // TODO: Kludge! and // TODO: There has to be a better way! :)

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[Jeremy Falcon]

Marc Clifton wrote:

Liberally sprinkle code with // TODO: Kludge! and // TODO: There has to be a better way!

I do the same thing too. :laugh:

Jeremy Falcon

[grolarbear]

Personally I find any issues that arise from scope can be resolved by the immutability of objects. I have no idea if this is good practice, but passing object references around or just having a global or high-up object with important stuff is how I like to do it.