react-native-reanimated: Potential memory leak with arrays in shared values

Description

I’m noticing a spike in memory usage over time when updating a shared value in react-native-reanimated-2. I suspect that it may be an issue in C++ when deleting array pointer references.

Expected behavior

Memory usage should stay the same over time. I left this code running for 10 minutes and checked the memory usage through xcode and it was much higher.

Shareable value pointers should be cleared up when re-assigning the value but instead we are seeing 1131065 shared value pointer references:

Actual behavior & steps to reproduce

Create a react-native-reanimated-2 playground that reassigns a shared value to an object with an array and set an interval to continuously update it

Snack or minimal code example

import {useSharedValue} from 'react-native-reanimated';
import {View, Text} from 'react-native';
import React, {useEffect, useState} from 'react';

export default function AnimatedStyleUpdateExample(props) {
  const [obj, setObj] = useState();

  const randomObject = () => {
    const arr = [];
    for (let i = 0; i < 10000; i++) {
      arr.push({
        key: i,
        value: Math.random(),
      });
    }

    return {
      id: Math.random(),
      arr,
    };
  };

  const test = useSharedValue();

  useEffect(() => {
    const interval = setInterval(() => {
      setObj(randomObject());
    }, 500);

    return () => clearInterval(interval);
  }, []);

  useEffect(() => {
    test.value = obj;
  }, [obj, test]);

  return (
    <View style={{flex: 1, justifyContent: 'center', alignItems: 'center'}}>
      <Text>Hello World</Text>
      <Text>{test.value ? test.value.id : ''}</Text>
    </View>
  );
}

Package versions

name	version
react-native	0.65.1
react-native-reanimated	2.3.1
NodeJS	17.2.0
Xcode	13.2.1
Java
Gradle
expo

Affected platforms

• Android
• iOS
• Web