facebookexperimental/Recoil

Memory leak when using atomFamily/selectorFamily

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#366 opened on Jun 19, 2020

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 (22 comments) (13 reactions) (1 assignee)JavaScript (19,428 stars) (1,151 forks)batch import
help wantedperformance

Description

Hello there,

The resources created by atomFamily and selectorFamily are not being properly freed when the specific key changes or if the component using the related RecoilState<T> unmounts.

Since I believe that memory management isn't properly implemented yet, both utils should be marked as _UNSAFE.

https://codesandbox.io/s/cranky-booth-penix?file=/src/App.js

Contributor guide

Tech stack
javascriptreact
Domain
frontendperformance
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
blocked
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
ReactRecoilMemory management in JavaScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
The issue describes a memory leak in atomFamily and selectorFamily where resources are not freed when keys change or components unmount. Review the Recoil source code in the src directory (e.g., src/shared/AtomFamily.js or src/shared/SelectorFamily.js) to understand how atoms and selectors are created and stored. Check existing comments and the linked CodeSandbox for reproduction steps. Note that the issue has an assignee, so reach out to them or maintainers before starting work.