Recoil: Memory leak

I’m sure an example can be simplified, but somewhere between 0.0.7 and 0.0.10 memory leak were introduced.

import React from "react";
import { RecoilRoot, useSetRecoilState, atom, useRecoilValue } from "recoil";

const state = atom({
  key: "test",
  default: []
});

const Subscriber = () => {
  const setTest = useSetRecoilState(state);

  React.useEffect(() => {
    const u = old => {
      const item = Math.random();

      if (old.length >= 5000) {
        return [item, ...old.slice(0, -1)];
      } else {
        return [item, ...old];
      }
    };

    const t = () => setTest(u);
    setInterval(t, 10);
  }, []);

  return null;
};

const Test = () => {
  const test = useRecoilValue(state);
  return <div>{test.length}</div>;
};

export default function App() {
  console.log("render");
  return (
    <RecoilRoot>
      <Subscriber />
      <Test />
    </RecoilRoot>
  );
}

Codesandbox:
0.0.10: code, demo
0.0.7: code, demo

Sandbox with 0.0.7 version doesn’t have memory leak, as you might see here (app run about 2 minutes between heap snapshots). 0.0.10: 0.0.7:

About this issue

Original URL
State: closed
Created 4 years ago
Reactions: 1
Comments: 16 (6 by maintainers)

Most upvoted comments

We’re finalizing some changes for Concurrent Mode now, then can try to investigate this before the next release.

+10

drarmstr on Jul 28, 2020

@saltycrane - Thank you for the reproducer.

drarmstr on Aug 17, 2020

In case it’s helpful, here is a sample webapp with code that demonstrates symptoms of a memory leak:

Webapp: https://saltycrane.github.io/recoil-vs-context-grid-test/recoil?x=200&y=100 Repo: https://github.com/saltycrane/recoil-vs-context-grid-test

saltycrane on Aug 17, 2020

This is fixed in master, which we plan to release tomorrow. Please note that development builds will leak memory by pushing onto window.$recoilDebugStates. You can delete from this array if it causes you problems.

could you please make this more prominent in the documentation? thanks for the otherwise great lib 😃

wizzard0 on Feb 21, 2021

@drarmstr any ETA on the next release? we’re heavily dependant on Recoil and plan to migrate a huge application from redux to recoil. Thank you for creating a missing piece of React ❤️

Pretty soon, actually!

drarmstr on Sep 1, 2020

This is fixed in master, which we plan to release tomorrow. Please note that development builds will leak memory by pushing onto window.$recoilDebugStates. You can delete from this array if it causes you problems.

davidmccabe on Sep 2, 2020

@Nishchit14 I’ve myself migrated app to focal It has similar concepts and is battle-tested in production at Grammarly.

Give it a try.

opudalo on Sep 1, 2020