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Iman YeckehZaare
Iman YeckehZaare

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Can a React usestate update be nested in another useState functional update?

There are n items the user can vote on. There are two React states:

  • votes is an array of the user's votes on every item.

const [votes, setVotes] = useState({});

  • voteChanges indicates how many times the user changed their votes on any of the items.

const [voteChanges, setVoteChanges] = useState(0);

We have a database listener defined in a useEffect. When votes are added/changed in the database, the listener gets called. We need the state votes to compare every new vote with its previous value in votes to decide whether to set voteChanges to true. However, we cannot define votes as a dependency in useEffect, otherwise we will end up in an infinite loop. To get access to the current value of votes, we use its functional update. Is it okay to call setVoteChanges inside the functional update of setVotes? If no, why and how should we solve this problem?

useEffect(() => {
    databaseListener((changes) => {
      setVotes((oldVotes) => {
        const oVotes = { ...oldVotes };
        for (let change of changes) {
          const itemId =;
          const newVote =;
          if (oVotes[itemId] !== newVote) {
            setVoteChanges(oldCount => oldCount + 1);
          oVotes[itemId] = newVote;
        return oVotes;
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