codesandbox / codesandbox/codesandbox-client

When mounting and with StrictMode disabled, Component with useState hook sometimes once (as expected), sometimes renders twice (not normal)

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JavaScript
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Description

🐛 bug report

Preflight Checklist

  • I have read the Contributing Guidelines for this project.
  • I agree to follow the Code of Conduct that this project
    adheres to.
  • I have searched the issue tracker for an issue that matches the one I want
    to file, without success.

Description of the problem

When mounting and with StrictMode disabled, Component with useState hook sometimes once (as expected), sometimes renders twice (not normal), as seen in the console

How has this issue affected you? What are you trying to accomplish?

Having the exact same behavior as in other IDEs, should only render once.

To Reproduce

Consider this example and refresh the page after its fully loaded to see the behavior:

Link to sandbox: link
Your Environment
Software Name/Version
Сodesandbox 0.0.158
Browser Version 120.0.6099.200 (Official Build) (64-bit)
Operating System Windows 10

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the linked CodeSandbox reproduction and verify the behavior with StrictMode disabled, checking whether mounting the component causes one or two renders. Isolate the conditions that trigger the duplicate render; done means the component consistently renders once on mount under the reported setup.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, react
Domain
frontend
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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