$.isEmpty was added in https://gerrit.wikimedia.org/r/#/c/158369/ and I'm not sure what is it even supposed to do. It's likely that it's supposed to be removed, or maybe replaced with a different check.
- Mentioned In
- rMWe87975128ae7: Updated mediawiki/core Project: mediawiki/extensions/ContentTranslation…
rECTX148699770c14: Remove $.isEmpty check from the formatter tool
rMEXT94f8704df425: Updated mediawiki/extensions Project: mediawiki/extensions/ContentTranslation…
rECTXc6b992c5fd64: Remove $.isEmpty check from the formatter tool
$.isEmpty is defined in jquery.mwExtension. This module is still in the core, but it's deprecated, and no core modules load it any longer since June 20.
So this function doesn't exist. It works only if by chance this module is loaded is some other way. Some wikis added it, because they have gadgets that depend on it.