Exception from a finished function: Error: You must return a Promise in your transaction()-callback.

 

https://stackoverflow.com/questions/48623641/error-you-must-return-a-promise-in-your-transaction-callback

Error: You must return a Promise in your transaction()-callback

stackoverflow에 나와 있던 코드

return db
  .runTransaction(t => {
      t.set(docRef, chat, {merge:false}); 
      return Promise.resolve(); // Add this line.
  })
  .then( doc => {
     response.send();
  })
  .catch(err => {
     ...;
  })

내가 작성한 코드

 

function givePoint(uid,userMap, userHistoryMap){

const userRef = admin.firestore().collection("Users").doc(uid);

return admin.firestore().runTransaction(t => {

//point 추가

t.set(userRef, userMap, { merge: true } );

//userCollection에 history 추가

t.set(userRef.collection('point_history').doc(), userHistoryMap);

return Promise.resolve();

});

}