facebook / facebook/hermes

Feature Request: Support for Parsing YYYY/MM/DD Date Format in Hermes Engine

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enhancement
Dominant language
JavaScript
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Forks
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Avg merge
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Merged PRs (30d)
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Description

Problem

Date.parse('2025/5/15')

output: NaN

image

Solution

Additional Context

https://github.com/facebook/hermes/issues/136
https://github.com/facebook/hermes/issues/175
https://github.com/facebook/hermes/issues/647

Safari or Chrome support parse YYYY/MM/DD nowadays

image

image

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 at the Date.parse('2025/5/15') entry point and compare Hermes behavior with the linked issues and the stated Safari or Chrome behavior. Done means YYYY/MM/DD input such as 2025/5/15 no longer returns NaN and matches the intended parsing semantics.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript
Domain
compilers
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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