They can't do anything right now until they find someone to take Pamela's place(She was the cp teaher).

Hi Jesse, glad you're interested in the vectors section of advanced JS!

The processing.js (PJS) library Khan Academy uses isn't up to date by any measure, still around the ES5 level... so lots of syntax and functionality isn't defined or available for it yet.

This is likely the same issue with PVector math and methods, the vector library has likely been updated since KA last published the articles. This article does demonstrate the use of mag() though, maybe it will help some:

https://www.khanacademy.org/computing/computer-programming/programming-natural-simulations/programming-vectors/a/vector-magnitude-normalization

Also look carefully through the docs, there might be a few helpful hints in their discussions.

What is needed for them to update? I suppose I could create my own functions that emulate the functionality of the updated version. But. It has been a while since I've done constructors and JS syntax is new to me.

Before I found PVector I was doing my own calculations, which did work for direction by slope = y2-y1 over x2-x1, then making y= the result of y2-y1 and x=x2-x1. However magnitude was based on distance from p1 to p2, but I couldn't sort out normalizing because im not sure how to reduce the resulting fraction so that I could create a set magnitude to work with.

If you feel like you can improve the vector library, KA would really appreciate it... I would have to push for its implementation though, since things are slow in the CS section.
If you ever need to review, KA has courses with quick answers (and there's the internet, lol)!

Ill see what I can figure out. Can I get link to git?

Here's where you can pick a course for quick review based on your needs: https://www.khanacademy.org/computing/computer-programming

And here's a cool custom vector library a friend of mine created, be sure to check that out!!!
https://www.khanacademy.org/computer-programming/vector-functions/6237474057682944

Was a nice vector library, however he should have done it as a single constructor. If you nest functions inside of a function then it would be considered a constructor. The following link shows that in action. I've pasted the constructor in here, but it'll likely be easier to read if you click on the link or if I could get code formatting to work on here or KA's main site. 

https://www.khanacademy.org/computer-programming/bubbles/4863237360517120

var Bubble = function() {
//variables of the Bubble function {
this.x = random(0,width);
this.y = random(0,height);
this.red = 13;
this.blue = 102;
this.green = 105;
this.alpha = 100;
this.diameter = 24;
//}
//functions of Bubble {
//base display properties of a bubble {
this.display = function () {
//setsoutline to a pinkish purple with 20% seethrough (80% alpha)
//strokeWeight(1); //causes lag when over 1
stroke(0, 139, 181,80);
//sets fill to red with 50% alpha
fill(this.red,this.blue,this.green,this.alpha);
//places an ellipse at a random location on screen
ellipse(this.x,this.y, this.diameter,this.diameter);
};//}
//checks to see if each bubble in the array has been clicked{
this.clicked = function(){
var d = dist(this.x,this.y,mouseX,mouseY);
if (d<this.diameter/2) {
if (mouseButton === LEFT) {
this.x = mouseX;
this.y = mouseY;
}
if (mouseButton === RIGHT) {
this.red = 13;
this.blue = 102;
this.green = 105;
this.alpha = 100;

}

}
};//}
//changes the color of a bubble {
this.changeColor = function(){
this.red = 0;
this.blue = 255;
this.green = 255;
this.alpha = 125;
};//}
//checks to see if any two bubbles intersect {
this.intersects = function(obj2) {
var d = dist(this.x,this.y,obj2.x,obj2.y);
if (d < this.diameter/2 + this.diameter/2) {
return true;
} else {
this.red = 13;
this.blue = 102;
this.green = 105;
this.alpha = 100;
return false;
}
};//}
//shrinks bubbles {
this.shrink = function(){
if (this.diameter > 2) {
if (ABSORB === 1) {
this.diameter -= 0.02;
} else {this.diameter -= 2;}
}
};//}
//grows bubbles {
this.grow = function(){
if (true) {
if (ABSORB === 1) {
this.diameter += 0.01;
}
}
};//}
//Makes the bubbles move randomly +- 1 pixel on both the x and y axis. {
this.move = function() {
this.x += random(-1,1);
this.y += random(-1,1);
};//}
//}
};//}

Oh yes, he could certainly build a constructor and define it's methods; that's his next step. If you'd like to talk with him directly, there is a section under the program for questions and tips/thanks, so you could post some tips there and maybe work together, whatever you want!

I posted on your program as well, looks awesome!

Has anything happened during the past year that might help me do what I need to do? Please see my profile and the question I just asked the Community.

Thanks for any guidance you can provide.

-Steve-

Hi Steve, it would be better if you asked your question as its own post here, so it has a better chance at getting answered:
https://khanacademy.zendesk.com/hc/en-us/community/posts/new?community_post%5Btopic_id%5D=115000487007