Dr. McKay

appid, contextid, assetid, classid, instanceid, amount, name, market_name, market_hash_name See this guide id Same as assetid pos Not always present; this is the item's position in the user's inventory (starting at 1) background_color Hex code for the background color rendered for this item in the Steam inventory name_color Hex code for the name and border color rendered for this item in the Steam inventory icon_url Append this to https://steamcommunity-a.akamaihd.net/economy/image/ to get the item's image descriptions Array of objects containing human-readable description text lines tradable, marketable Self-explanatory type The text that goes under the game's name to the right of the square game logo in the Steam inventory when this item is viewed commodity Determines whether this item's Market listing uses buy orders exclusively (true), or individual listings with the possibility to submit buy orders (false) market_tradable_restriction Length in days that this item will be untradable after it's bought on the market market_marketable_restriction Length in days that this item will be unmarketable after it's bought on the market tags Array of tag objects; tags are used in the Steam inventory for filtering is_currency Always going to be false except for some Spiral Knights stuff (I think). You really don't want to deal with currencies, trust me. fraudwarnings Array of warnings that will be rendered in red when this item is viewed. If fraudwarnings exist, the item gets a red (!) icon in the Steam inventory

You're not meant to use the method I gave in conjunction with the confirmation checker. 
The confirmation checker (in simple terms) works by telling Steam every X seconds: "Hey, I wanna confirm everything waiting to be confirmed". It will tell steam even if there is nothing waiting to be confirmed thus the load it puts on servers - imagine loads of bots doing this. 
Whereas the method I put tells steams servers: "Hey, I wanna confirm this specific trade". Therefore, it only tells steam when there is something to be confirmed. 

Using a confirmation checker puts unnecessary load on steam's servers. 
 
After receiving or sending a trade offer, obtain the offer's ID and then call this method:
community.acceptConfirmationForObject('YOUR_IDENTITY_SECRET', 'OFFER ID', (err) => { if (err) { console.log(err); } // code here })  

I'm not sure I believe you.

https://www.npmjs.com/package/steamid

Yes, that's what the code I posted is for.
Yes, yes, yes.

You don't need to log into the client to send or receive trade offers, no.
You can use a proxy like:
 
const SteamUser = require('steam-user'); let user = new SteamUser({ httpProxy: 'http://user:[email protected]:5678' });  

I'm sorry, I don't think I can really help you much more with this. I haven't seriously touched any GC-related code in a good while, and the most I could do is experiment, which it seems is what you're doing anyway.

const SteamID = require('steamid'); const URL = require('url'); let link = 'https://steamcommunity.com/tradeoffer/new/?partner=46143802&token=aaaaaaaa'; let steamid = SteamID.fromIndividualAccountID(URL.parse(link, true).query.partner);  

https://github.com/DoctorMcKay/node-steamcommunity/wiki/SteamCommunity#sessionexpired

I guess you should confirm your email.

By sleeping synchronously, you're preventing the module from actually sending the message over the network. You should almost never sleep synchronously in JavaScript.
You're looking for the setTimeout function.

I suppose theoretically it would be possible if you used a bot to get some new cookies for steamcommunity.com, then requested steamcommunity.com/chat with those cookies and proxied the response back to the browser.

https://steamerrors.com/15

Iam using this, it works fine, when I have time, I will look it up, probably after my finals. 
 if(oldState == 12){       return;     }

You need to check the descriptions array of the item in question and look for the unusual effect tag (after making sure it's a TF2 item, of course). And you can check the color to see if the item is of Unusual quality.

Fixed it, apparently I've been initializing a new SteamCommunity object in my main file. Thanks anyway, explaining this to someone really cleared my mind up
 
Cheers!

Working out change is similar to the popular coin change problem, except you don't have infinite amount of each coin. 
 
Here's how I would do it:
Convert the price to scrap. Then using the coin change problem work out the least amount of scrap needed. In this case your coins would be 1, 3, 9, and key price in scrap being scrap, rec, ref and key price in scrap respectively. 
 
Look up the coin change problem and develop a function to work out the change. It's hard but also good to develop your coding skills. I wouldn't recommend to steal someone else's code since you don't know what it's doing and at the end of the day if your bot gets scammed it is your fault for not knowing how your code works. 

Firstly, look into using acceptConfirmationForObject in place of the confirmation checker.
Secondly, you have a potential bug in using the disconnected event to log into a new account. The disconnected event can also be emitted if the connection to Steam drops temporarily but will be automatically re-established. You should probably set a flag when you call logOff() so you know if the disconnected event was in response to that.
Finally, to your main question, you should call manager.shutdown() when you log out of an account before logging into a new one. That should solve your problems.

getUserDetails cannot be called unless an offer is active, so you need to use it before you send a counter offer.
Using the counter() method will return a new, unsent trade offer object which, when sent, will be sent as a counter offer. Each offer can only be countered once, so if you try to send two counter offers (either by calling counter() twice or by calling duplicate() on a counter offer), it won't work.
In essence, the ID of a trade offer sent to you can be used in place of a trade offer access token (sort of, not literally) in order to send a trade offer, but only once. Once you send one counter offer, the original offer goes into "Countered" state and it can't be countered again.

That's almost impossible, unless you have a very unique name. 
The reason it wouldn't work is because anyone can have the same username as anyone else. 
Unless you're talking about the login username. I don't think you can, because that's hidden from everyone apart from the owner of the account itself. 

Tnks a lot doc!, very appreciated for the patience answering,
Have a great week!
Rami~

Maintaining many npm packages is hard. If you want it to be solved, try making your own solution.

To handle errors:
client.on('error', function(err) { // do something with err (which will never be null or undefined in this event) }); You aren't going to be able to do anything with limited inside of the loggedOn event. The data isn't going to be available yet. loggedOn gets emitted when Steam sends us back the logon response saying that your logon was successful, but Steam doesn't send us our account limitations for another second or so, which is why the data is undefined/null inside of the loggedOn event.

Sure, you could use steamstore for this.