Yes, but i used `let` as a variable name and it didn't show an error is it that `let` isn't useful? So its not in khan academy

I used let as a variable name i mean

I thought variables can't have spaces

We can use those in es6 if you put

//jshint esnext:true

at the top

thanks that worked! i have no idea why this wasn't supported already because its from SEVEN years ago but thank you so much

I don't think KA has any plans to update their version of JavaScript.  My guess is that they would have to rework much of the curriculum, and many people's existing programs that they adore would stop working.

i see your point with the first thing you said, but that's not how javascript works, you can very much still use var in current javascript, so it shouldn't break ppls projects. 

Dino

Are you addressing my post from last week?  Is everything in KA's version of JavaScript still supported in the most recent version of JavaScript?  Or are you suggesting KA should only make a partial update, to allow `const` and `let`?

(It's probably moot, since even their current version has broken things that were reported to them many years ago that have never been fixed, so I have little expectation that they will put any effort into fixing anything about their JavaScript implementation.)

No, I do not think I did, because I do not remember reading any of your posts. Just to be sure, I went to your profile, but still could not find any posts from you last week. When I was trying to find that, I read a lot of your feature requests/bug reports and they seem really well-thought out and well-written, though!

To your second question about Khan Academy's Javascript,I did a bit more digging and wrote two feature requests myself about it. In short, let and const variables do not work because processing.js, the library they use to allow javascript-in browser, is very much out of date, and is based on java translated to javascript instead of just plain JS. I do not think it is possible for it to be altered to allow them.

If you want more info about that, you might wanna check out my 2 feature request posts, https://support.khanacademy.org/hc/en-us/requests/493627 and https://support.khanacademy.org/hc/en-us/requests/494042

I think they /are/ going to fix this, because it is a potential vulnerability.

Oops; I meant "comment rather than "post". (I used the term "post" because in the KA discussions "post" is the general term for a Question, Answer, Comment, or Tip/Thanks.  I see that here in the Support Community, "post" is the term for the first thing posted that starts a new thread.  I'm sorry about the confusion.)
I meant, were you addressing the comment I made last week in this thread that was immediately before your comment that starts "i see your point with the first thing you said".  

I cannot see anything when I follow those links; I get the error 

The page you were looking for doesn't exist

You may have mistyped the address or the page may have moved

Since the links have "requests" in the web address, I am guessing they were requests to KA staff, rather than posts in the Support Community.  I don't know whether other users can view such requests.

JaniceHolz

Yes, yes I was. Var variables are supported in current Javascript, from what I understand, they are just something to only use when you absolutely have to because they are global variables that can be changed into completely new datatypes and do not have to be declared before being used, so they make it easy to make mistakes. 

oh ok I guess that makes sense. I've just copy and pasted my first request to them below, since the second has much of the same information, just from a different angle: 

Dino
Thank you for sharing the additional information.

Do you know whether the existing programs would work if KA updated their library?

JaniceHolz

 I don't know, exactly. p5 includes a lot of 3D functionality, but I don't know if KA wants to implement it, so I have not written 3D functionality in any of the additional features of a function.
I looked at every function listed in KA's documentation and checked if there's a function of the same name or if there's an equivalent function in p5.js's documentation, and made a HUGE list.

Shapes
-All shape and complex shape functions listed appear to be supported by p5, with the same names as the processingJS library
Colors
-background() is supported, and p5 supports HSB and CSS and hex code colors as well using the colorMode() function. I tried it out on the KA javascript window and setting the color mode to HSB doesn't bring up an error message but doesn't appear to work, either. The KA window supports CSS named colors and percentage RGB notation. It does not throw up an error code but does not support hex RGB notation, example: background('#fae');, or Integer RGB or RGBA notation, or Percentage RGBA notation (it ignores the transparency variable). KA does throw an error code for a p5.Color object (example: let c = color(0, 0, 255); background(c);).
-fill is supported, and p5 processes a one integer value in fill as grayscale, same as the current KA javascript window.
-blendColor() is NOT SUPPORTED by p5.js or at least is not listed in the documentation anywhere. It doesn't seem like an important function, though, so that's good. I also don't know if there's a library that has that function that KA could use with p5.js.
-brightness() is supported, but KA does NOT seem to correctly use brightness(), but I think that's because it doesn't actually support HSB colors in the first place. The brightness value WILL CHANGE in projects that use brightness() to assign color, but that would change anyway if KA fixed the brightness function. 
-everything else in color is supported
Text
-All text functions appear to be supported

Transform
-pushMatrix() and popMatrix() are supported in p5 under the different names of push() and pop(), respectively
-PrintMatrix is NOT SUPPORTED by p5. I do not know why
-Everything else is supported

Environment
-draw = function() { } is renamed in p5.js to function draw() {}, but acts the same
-playSound() sound is NOT SUPPORTED, instead on p5.js you have to loadSound in the preload() function its ready for setup() or draw(). I think that KA could automatically include the preload function at the start of every project that uses a sound, given that there is a finite number of sounds allowed. playSound() is replaced by SoundName.play().
- Program.assertEqual, a debugging tool, is NOT supported.
-Program.restart is NOT supported
-I think that the Program object is unique to Khan Academy, so they could probably be rewritten in p5.js and then used by students. I don't know much about programming though, so I don't know if I'm explaining this using the correct terminology.
-Everything else in Environment is supported by p5.js

Mouse
-mouseClicked = function() { } is renamed as the more concise function mouseClicked() {}, much like the draw function
-mouseReleased = function() { } is renamed as function mouseReleased() {}
-mouseDragged = function() { } renamed as function mouseDragged() {}
-mouseOut = function() { } has a p5 equivalent of mouseOut(), but that function is not only for a canvas but can be assigned to any element. However, KA makes a canvas in every javascript project, so KA could probably assign the mouseOut function to the canvas element automatically.
-mousePressed = function() { } is trimmed down to function mousePressed() {}
-mouseMoved = function () {} is renamed as function mouseMoved() {}
mouseOver = function() { } is renamed as SomeElement.mouseOver()
-All other mouse functions are unchanged and supported

Keyboard
-keyReleased = function() { } is renamed to function keyReleased(){}
-keyCode is kept the same, but should be able to check for more keys than Processing.js.
-keyPressed = function() { } is renamed as function keyPressed() {}
-keyTyped = function() { } is renamed as function keyTyped() {}
-all other Keyboard functions are supported 

Math
-random() is supported with additional functionality of being able to pick a random string from a list of strings
-round() is supported with additional feature of being able to round to a set number of decimal places determined by an optional parameter
-min() is supported, and adds the ability to compare more than 2 numbers at a time
-max() is supported, and adds the ability to compare more than 2 numbers at a time
-Pvector() replaced with createVector(), the best way to declare a vector, and p5.Vector([x], [y], [z]) 
-map() is supported with the added feature of being able to clamp the number to the target range using an optional boolean 6th parameter
-Random.nextGaussian/Random(seed) (ProcessingJS only allows for Gaussian) is replaced by 3 functions: randomGaussian() for a normal distribution, random() for a pseudorandom number, and randomSeed() to make the functions produce the same results each time a sketch is run.
-Everything else in Math is unchanged and supported in its current state

Trigonometry
-cos(deg) is replaced by cos() which p5 sets radians as the default, so to avoid breaking projects KA might want to set the angle mode to degrees at the start of a project
-the rest of the trig functions are automatically set to radians too
-angleMode = "degrees"/"radians"; is replaced by angleMode(DEGREES/RADIANS)

Date & Time
-Everything in Date & Time is Unchanged

Debugging
-debug(arg1, arg2, ...) just prints various arguments to the console, and is replaced by a variety of console commands, like console.log(). However, those console commands currently do not work in KA, so I do not know if they would print to a visible console or to a console only able to be seen when you inspect the page
-println(data) is NOT supported, instead in p5.js, each print("text") creates a new line of text. Also, print(msg) is described as printing to the browser console, and I don't know how KA currently has print() go to the canvas console instead
-print(data) is supported, but is described as printing to the browser console. Also, print() (without anything in the parenthesis) "opens the browser's dialog for printing documents." which is not a function KA needs, so maybe they should set up Oh Noes to flag it as an error

JavaScript
-var drawWinston = function() { }, to define a function, is renamed as function drawWinston() {}, but can still be called like a variable, if I am reading the docs right
-everything else is still supported in that form by p5.js

In conclusion, the main problems that could break people's code are the more concise function definitions, the print/println outputting to the browser's console maybe, PVector being replaced, Random.nextGaussian/Random(seed) being replaced, the Program constructor object not being supported, blendColor() not being supported, playSound being replaand printMatrix() not being supported. The problems that could make someone's project not work or look the way its supposed to are the pr.js brightness function fixing KA's broken brightness() function, and trig functions being automatically set to radians instead of degrees. This is honestly more compatibility issues than I was expecting, but most could be solved by a simple find/replace, or putting hidden code in the window, which KA already does. A lot of this could have been avoided by KA switching libraries years ago, but they didn't so here we are. 
Thanks for reading! I know this was super long

PS for some reason at the bottom of KA's documentation, they have a link that says "ProcessingJS" that actually takes u to p5.js's documentation??? words cannot describe how confused I am

Wow -- that is way more detail than I needed.

Is the summary that there would be compatibility issues?  If fixing those issues would take very much staff time, I think it unlikely that KA would take it on.  There are easily-fixed issues with their implementation of JS that they were told about years ago that they have done nothing about.  I've been waiting over 2 months for them to fix the transcript below a CSS talk-through.

JaniceHolz

sorry for the TMI, I didn't know exactly what would and would not work so I looked up every function listed in KA's documentation individually in the p5.js documentation going down the list. In retrospect, I should have just kept that document to myself and post a condensed version. I have Covid right now and I don't think that helped matters either lol.

Also, I was looking at the p5.js website and it looks like they are updating it to version 2.0, which will become the default in August 2026 (source: https://medium.com/processing-foundation/p5-js-2-0-you-are-here-f827f40519a7). That August, they will also stop supporting p5.js version 1. Unfortunately, v2 will not support the shape functions that ProcessingJS and p5.js v1 does. Fortunately, they are working on add-on libraries to keep that functionality (source: https://github.com/processing/p5.js-compatibility), but they seem like they still have some issues. Somehow, it might be in KA's best interest to wait to switch until they polish the add-on libraries, since the shape.js function is so integral to every project here on Khan Academy. 

TL;DR It might be for the best for KA to wait until August 2026 or wait until the shape.js add-on library is polished to switch to p5.js. so maybe their chronic inaction might actually help them out for once

I'm so sorry you have Covid.  I hope you have a good support system and that you are healthy again soon.