jquery / jquery/jquerymobile.com

TypeError: Cannot read properties of undefined (reading 'concat') when using jQuery 3.x

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Dominant language
HTML
Stars
57
Forks
69
PR merge metrics
No merged PRs in 30d

Description

Error:
Cannot read properties of undefined (reading 'concat')

I'm using jquery 3.3.1 and I've tried 3.6.1 also

jquery mobile is 1.4.5

Contributor guide

Open the contributing guide

First steps

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  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

The report names no files, tests, or reproduction, only jQuery 3.3.1/3.6.1 and jQuery Mobile 1.4.5. Start by creating a minimal reproduction for the undefined concat error with those versions, then identify the failing project entry point. Done means the cause is confirmed and a regression test or documented compatibility result covers the issue.

Written by the indexing model from the issue text.

Assessment

Tech stack
jquery
Domain
frontend
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
20/100

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