From Longman Dictionary of Contemporary English(just) you wait(just) you waitspokena) British English used to warn or threaten someoneI’ll get you back for what you’ve done, just you wait.b)used to tell someone you are sure something will happenIt’ll be a huge success. Just you wait. →wait
Examples from the Corpus
(just) you wait• It'll be a hugesuccess, just you wait.