How does V8 handle scopes when WebAPI is used [duplicate]

Question

I know JavaScript is single threaded non blocking, and hands things such as setTimeout() to the web api, but how does it handle scopes?

lets say there is a function like

function example()
{
  const x = 10
  setTimeout(() => { console.log(x) }), 100)
}

example()

How does it keep track of the variables in that scope? or do they not get deleted?