Make WordPress Core

Opened 9 months ago

Last modified 3 weeks ago

#46110 assigned defect (bug)

IE11: JS "Syntax error" related to wp-polyfill-formdata

Reported by: afercia Owned by: atimmer
Milestone: 5.4 Priority: normal
Severity: normal Version: 5.0
Component: Build/Test Tools Keywords: has-screenshots needs-patch
Focuses: javascript Cc:
PR Number:


In Internet Explorer 11, there's a JavaScript "Syntax error" related to wp-polyfill-formdata. The error happens in various pages, e.g. in edit.php and post.php.


IE11 doesn't support "arrow functions" and other ES6 features in that file. Asked for feedback on Slack #core-editor and it was pointed out that seems core is using the wrong file from the package.

Wrong version used in core:


Correct version used in the Gutenberg plugin:


Introduced in [43719] /Cc @omarreiss @atimmer

Change History (9)

#1 @ocean90
9 months ago

  • Component changed from General to Build/Test Tools
  • Keywords needs-patch added
  • Milestone changed from Awaiting Review to 5.1.1

The file is only loaded if SCRIPT_DEBUG is set.

We could ask the author to include a formdata.js in a /dist directory. They are using the Closure Compiler so the WHITESPACE_ONLY option would fit for this.

#2 @atimmer
9 months ago

I've asked the author of the library to include a non-minified build file: https://github.com/jimmywarting/FormData/issues/69.

I see two possible workarounds:

  • Build the file ourselves in the webpack configuration.
  • Ship the minified file as the non-minified file.

The second one is easier to implement, the first one is better.

#3 @netweb
8 months ago

  • Owner set to atimmer
  • Status changed from new to assigned

This ticket was mentioned in Slack in #core by lukecarbis. View the logs.

8 months ago

#5 @lukecarbis
8 months ago

  • Milestone changed from 5.1.1 to 5.2

#6 @jorbin
7 months ago

  • Milestone changed from 5.2 to 5.3

Bumping due to lack of activity upstream.

#7 @afercia
5 months ago

Noting the upstream issue on GitHub has been automatically closed by the "stale bot" because of lack of activity and seems the project maintainers aren't inclined to ship a non-minified version.

This ticket was mentioned in Slack in #core by david.baumwald. View the logs.

3 weeks ago

#9 @netweb
3 weeks ago

  • Milestone changed from 5.3 to 5.4

Due to lack of updates, punting this to 5.4 to clear the way for 5.3

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