PrismJS / PrismJS/prism

async + defer can result in DOMContentLoaded not being fired

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#3,535 5 comments 0 reactions 0 assignees View on GitHub

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Dominant language
JavaScript
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Description

Information:

  • Prism version: 1.28.0
  • Plugins: languages=markup+css+clike+javascript+bash+css-extras+git+go+java+json+json5+makefile+markdown+markup-templating+php+regex+shell-session+sql+iecst+typescript+yaml
  • Environment: browser

Description
When loading the script with async and defer, the automatic highlighting doesn't always work.

I think this is due to readystate === interactive and it seems that DOMContentLoaded will not fire when that is the case.

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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

Start by reproducing the browser case with Prism loaded using both async and defer, then inspect the automatic highlighting path and its DOMContentLoaded/readystate handling. Done means automatic highlighting works reliably in this loading configuration without preventing DOMContentLoaded from firing.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript
Domain
frontend
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
35/100

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