FirebaseExtended / FirebaseExtended/reactfire

useFirestoreCollection triggers a double render

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#484 4 comments 2 reactions 0 assignees View on GitHub
v5
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Description

Hi,

Seems like `useFirestoreCollection` always triggers unnecessary render when fetching data (suspense is **on**). Similar behavior is also the case for `useUser`.
There's a chance I'm simply using the API wrong, so please advise if so :)

### Version info

**React:** 17.0.2

**Firebase:** 9.1.3

**ReactFire:** 4.2.0

### Test case

```javascript
const q = /* whatever query */;
const queryResults = useFirestoreCollection(q);
console.log(queryResults);

```

### Expected behavior

`console.log` is called once.

### Actual behavior

`console.log` is called twice.

Ultimately, what I'm trying to achieve is a code similar to the one below

```javascript
const queryResults = useFirestoreCollection(query);
return queryResults.data.docs.map((d) => /* render */);
```

that renders only once when the data is fetched (and then only when there're changes in the collection).

Contributor guide

Open the contributing guide

Research direction

Start by reproducing the behavior with the useFirestoreCollection test case and compare it with the similar useUser behavior. Inspect those hook entry points to determine why fetching with Suspense causes console.log to run twice. Done means fetching data produces one render, while later renders occur only when the collection changes.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, react
Domain
database, frontend
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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