If the US dissolves for whatever reason and goes into a state of anarchy what would happen to the rest of the world?

Countries with mutual treaties are going to get attacked. China would definitely take Taiwan and maybe the Philippines.

At first, LOTS of “I told you so” comments on social media. These would quickly disappear as the shit really hit the fan.
- Lol you think there's gonna be social media
  
  You do realise that other countries have internet servers too?
  Americans might lose access to social media, and the internet in general, but much of the world will still be online.
  
  You think there would be no social media left if Twitter, Reddit, Facebook & Co. went down? Using Lemmy?
  
  Excellent point

We would need to ignore how destitute the rest of the world would need to be for a superpower to full-on collapse in its entirety. I'm also assuming you mean that there's zero semblance of order or organized society.
The military would get recalled and leave American bases, strategic territory, and other occupied areas undefended and open to capture. Economies that rely heavily on trade with the US would need to find new trading partners to prevent potential economic collapse and it might not even save them if they can't get similar enough agreements or pricing. There are countries that also rely heavily on straight US aid, either monetarily or goods, that would collapse themselves or force them to align with whichever country would give them new aid. Global healthcare would dip without the drugs manufactured by the US. No American commodities like oil or food makes prices of those commodities go up everywhere else.
People around the world would be afraid. Whatever you may think of the American government and US politics, the average US citizen/resident is quite removed from the goings on of the federal government. The states on their own have a lot of independence and some would likely survive a collapse in federal leadership, but if federal, state, and local government all collapsed together it would be something serious enough to warrant attention from other countries with similar structure to the US.
- Red states would be fucked without that stream of blue state money coming in...lol
  
  And that's a good thing
- Is oil an American commodity? Appreciate this might be a different #nostupidquestions.
  I always assumed that oil was primarily a middle eastern thing hence the US's interest in it.
  
  https://www.eia.gov/todayinenergy/detail.php?id=61545
  The middle east is definitely a major producer of oil, but the US produces even more.
  However, what would likely impact the world more than a reduction in crude production is that the US has the largest refinery capacity and exports 15% of the petroleum products it makes. Global refinery capacity is 103.5 million barrels per day, the US constitutes 18.4 million of that. While it's relatively quick for other oil producing nations to bump up their crude production, any major disruption in refining would have huge effects on the prices of petroleum products. Refineries are very expensive and complex. They cannot be scaled up quickly unless there is idle capacity to bring back online.

The next biggest economy would likely fill the power vacuum, which at the moment would be China.
European countries would likely band together but still align their policies closer to Russian polices because they're a more imminent threat than China.
There would probably be several small brush wars as countries try to to consolidate power amongst regional areas like North America and the Middle East.
Fragile ceasefires backed by American influence would pretty quickly dissolve like between North and South Korea.
And in a few decades everything will settle into a new "normal" just like it did when other great empires have lost their influence.

Multinational corporations and crime syndicates and others would be at each others throats, nobody would enforce trillions worth of contracts, USD would be meaningless, all govt services would attempt to go private. mass migration attempts.

Mexiko and Canada would have a bigger coastline

dissolves for whatever reason
As if we all don't know the reason.
- I think the point is the reason didn't matter for proposed question
  
  That makes sense to me. Haha

Stay tune. We are headed that way.

The crash of the US market would bankrupt many organisations that rely on US liquidity to exist.

We would probably have to learn Chinese instead of English.

War
- That’s already happening, specifically because the US exists. De-escalation is more likely, when the US is no longer funding and training terrorists.

Well Peace for one moment & another replacement the second moment

The world economy would utterly collapse.

That would be pretty nice to see functioning anarchic societies. You are using the wrong term, you mean anomy.
I think we will get a bit of a taste of that in the next years.
- OK I read the article two things I have to say. WTF. And how absolutely we have a term for it. But after that it was a great read. But comparing it its still fucked up
- I learned a thing, thanks!
- We had somalia
- Why do you say anomie instead of anarchy is the term OP should be using?
  
  Because most people use the word anarchy for a society without rules and without order. Right of the strongest, 365 days The Purge or something like that. But anarchism isn't about that, but about a peaceful way of living without hierarchies and rulers. I was sure, that is not, what OP meant.

America gets a cold, the world gets the flu.
And that is just the economic impact.

World politics would become more complicated. This could lead to more wars and nationalism

Don. I've put up with your shenanigans for months. Enough. Stop asking stupid vitriolic questions.

Economic chaos for a little while, and then everyone would just go on with their lives. Economically it would matter of course; America became the richest power after the first world war when all of Europe needed loans to fight their "great war", causing the greatest transfer of wealth the world had ever seen.
But culturally, I'm betting the number of people who would give a shit if the United States stopped bossing everybody around is far less than they think it is.
The american sense of importance is strongest mostly in their own heads.

There are going to be a lot of wars to redraw boundaries, especially in Africa.

We would give a brief "Oooohh"
and then go on with our lives.
- Somehow I doubt that would be the result.
  
  The powers already out in their mom's basement. All they got is a cell phone so...