I don't even - one of my first coding attempts?

thing.js

function NumberError(msg){
	this.name = "NumberError";
	this.msg = msg|"";
}

NumberError.prototype=Object.create(Error.prototype);
NumberError.prototype.constructor=NumberError;

Array.prototype.bigUnion = function(){
	var a=[];
	for(var z=0;z<this.length;z++)a=a.concat(this[z]);
	return a;
}

function s(x){
	for(var i=2;i<=Math.sqrt(x);i++) if(!(x%i)) return i;
	return x;
}

function l(x){// largest divisor of x
	for(var i=Math.ceil(Math.sqrt(x));i>=2;i--) if(!(x%i)) return x/i;
	return x;
}

function isPrime(x){
	return s(x)==x;
}

var memoized = [];

function isB(x){	// Baumic number check
	if(memoized[x]) return memoized[x];
	memoized[x]=(new Tree(x)).isB();
	return memoized[x];
}

function Tree(x,f1=s){
	this.top = new node(x);
	var i=0;
	var c=this.top;
	while(!isPrime(c.body)){
		c.attach(f1(c.body),c.body/f1(c.body));
		c=c.children[1];
	}
}

Tree.prototype.disp = function(){
	return this.top.disp();
}

Tree.prototype.isB = function(){
	var yF=this.family();
	return!!(yF.indexOf(yF.length)+1);
}

Tree.prototype.family = function(self){
	return this.disp().replace(/ => \(/g,",").replace(/\)/g,"").split(",").map(Number);
}

function node(x){
	if(isNaN(parseInt(x))) throw new NumberError("Input ("+x+") not a number")
	this.body = x;
	this.children = [];
}

function nodify(type,input,z){
	switch(type){
		case "array":
			return input.map(function(e){return e?z?(new node(e)).factor():new node(e):""});
		break;
		default:
			return new node(input);
		break;
	}
}

function n(input){
	return input.map(function(e){return (new node(e)).factor()});
}

node.prototype.disp = function(){
	return this.body + (this.children.length?" => ("+this.children.map(function(e){return e?e.disp():"?"})+")":"");
}

node.prototype.right = function(){
	if(this.children.length) return this.children[1].right();
	return this.body;
}

node.prototype.attach = function(){
	a = Array.from(arguments);
	for(var _i=0;_i<a.length;_i++){
		y=a[_i];
		if(!(y instanceof node)) try {y=new node(y)}catch(e){if(e instanceof NumberError)throw Error("Invalid node")}
		this.children.push(y);
	}
}
var g=0;
node.prototype.factor = function(f=l){
	ui=[f(this.body),this.body/f(this.body)];
	if(!isPrime(this.body)){
		nu=n(ui);
		console.log(ui,this.body,nu)
		this.children = nu;
	}
}