A few days ago, per report on RU wiki, if a page contains a map, and the user has enabled Editing / Show previews without reloading the page in their preferences, the page crashes after the second page preview.
@Vort has reported that the issue is here:
mw.hook('wikipage.content').add(function($content){var mapsInArticle=[],promises=[];$.each(maps,function(){ maps.pop().remove(); // <-- missing remove });$content.find('.mw-kartographer-map').each(function(){var data,container=this,$container=$(this),deferred=$.Deferred();data=getMapData(container);if(data){mapsInArticle.push(initMapBox(data,$container));promises.push(deferred.promise());}});$.when(promises).then(function(){mw.hook('wikipage.maps')
stacktrace:
VM85:108 Uncaught TypeError: Cannot read property 'remove' of undefined at <anonymous>:108:689 at Function.each (load.php?debug=false&lang=ru&modules=ext.CodeMirror.lib|jquery%2Cmapbox%2Coojs-ui-core%2Coojs-ui-widgets|oojs-ui.styles.icons-editing-advanced&skin=vector&version=0tjdd2i:259) at <anonymous>:108:658 at fire (load.php?debug=false&lang=ru&modules=ext.CodeMirror.lib|jquery%2Cmapbox%2Coojs-ui-core%2Coojs-ui-widgets|oojs-ui.styles.icons-editing-advanced&skin=vector&version=0tjdd2i:300) at Object.fireWith (load.php?debug=false&lang=ru&modules=ext.CodeMirror.lib|jquery%2Cmapbox%2Coojs-ui-core%2Coojs-ui-widgets|oojs-ui.styles.icons-editing-advanced&skin=vector&version=0tjdd2i:302) at Object.fire (<anonymous>:4:11) at <anonymous>:498:556 at fire (load.php?debug=false&lang=ru&modules=ext.CodeMirror.lib|jquery%2Cmapbox%2Coojs-ui-core%2Coojs-ui-widgets|oojs-ui.styles.icons-editing-advanced&skin=vector&version=0tjdd2i:300) at Object.fireWith [as resolveWith] (load.php?debug=false&lang=ru&modules=ext.CodeMirror.lib|jquery%2Cmapbox%2Coojs-ui-core%2Coojs-ui-widgets|oojs-ui.styles.icons-editing-advanced&skin=vector&version=0tjdd2i:302) at Object.deferred.(/w/anonymous function) [as resolve] (https://ru.wikipedia.org/w/load.php?debug=false&lang=ru&modules=ext.CodeMirror.lib%7Cjquery%2Cmapbox%2Coojs-ui-core%2Coojs-ui-widgets%7Coojs-ui.styles.icons-editing-advanced&skin=vector&version=0tjdd2i:305:603)