How to create pagination using orderByChild, equalTo and endBefore from Firebase Query? React Native-CodePudding

I am working in a pagination method where I want to load more data based on category type. Currently I am getting an Error:

endBefore: Starting point was already set (by another call to endAt, endBefore or equalTo).

I know I can't use endBefore and equalTo but I can't find a way to get what I want. If there is any approach to solve this will be amazing. Here is what I have of code.

function getPost() {
  const vibesQuery = query(
    vibesRef,
    orderByChild("category"),
    equalTo(categoryType),
    limitToLast(2)
  );
  onValue(vibesQuery, (snapshot) => {
    const data = snapshot.val();
    if (data) {
      const vibesArray = Object.values(data);
      setVibes(vibesArray.reverse());
      setLastVibe(vibesArray[vibesArray.length - 1][sortingType]);
    }
  });

function getMorePosts() {
    const vibesQuery = query(
      vibesRef,
      orderByChild("category"),
      equalTo(categoryType),
      endBefore(lastVibe),
      limitToLast(2)
    );
    onValue(vibesQuery, (snapshot) => {
      const data = snapshot.val();
      if (data) {
        const vibesArray = Object.values(data);
        setVibes([...vibes, ...vibesArray.reverse()]);
        setLastVibe(vibesArray[vibesArray.length - 1][sortingType]);
      }
      setIsMoreLoading(false);
    });
 }

My data structure is:

{
  "-LbzPjzin65Rt3ZIK1Lo": {
  "caption": "Great",
  "category": "OUTDOORS",
  "cityVibe": "Chino",
  "stateVibe": "CA",
  "creationDate": 1573942298.999069,
  "fullname": "Bryant",
 }, 
  "-LbzPjzin65Rt3ZIK1Io": {
  "caption": "Amazing",
  "category": "OUTDOORS",
  "cityVibe": "Chino",
  "stateVibe": "CA",
  "creationDate": 1576382057.7584639,
  "fullname": "Bravo",
 }, 
  "-LbzPjzin65Rt3ZIK1Ao": {
  "caption": "Beatiful",
  "category": "OUTDOORS", <-- THIS IS MY (categoryType)
  "cityVibe": "Chino",
  "stateVibe": "CA",
  "creationDate": 1586638159.889124, <-- THIS IS MY (lastVibe) 
  "fullname": "Bravo",
 },
  "-LbzPjzin65Rt3ZIK1Bo": {
  "caption": "Fantastic",
  "category": "OUTDOORS",
  "cityVibe": "Chino",
  "stateVibe": "CA",
  "creationDate": 1604361787.34916,
  "fullname": "Bravo",
 },
}

If there is any additional information, let me know and thank you so much!

CodePudding user response：

There is no way to pass multiple property values to filter on. What you can do in this case, it use Firebase's startAt/endBefore overload that takes two parameters. The first value is the property value you want to start/end at, but the second parameter is the key of the node you want to start/end at in case there are multiple matches on the first value.

So if you have the key of the last vibe in a variable called lastVibeKey, you can do:

query(
  vibesRef,
  orderByChild("category"),
  endBefore(categoryType, lastVibeKey),
  limitToLast(2)
);