The current implementation mutates the state. If there would be no better solution, we should do something like:

setQueries(prevQueries => {
  const newState = {...prevQueries};
  delete newState[threadID];
  return newState;
}),

but there's a better solution

setQueries(prevQueries => {
  const {[threadID]:deleted, ...newState} = prevQueries;
  return newState;
}),

(but Flow might complain about unused variable deleted)

What do you think about changing the approach so that a thread id is a parameter of set query?

Where this context will be rendered? Are we sure that this will always be true? Can we avoid having this invariant?