"TypeError: Cannot read property 'started' of undefined at ./src/reducers/eventLogging.js.module.exports (https://ca.wikipedia.org/w/load.php?debug=false&lang=ca&modules=ext.popups&skin=vector&version=1gn0xfc:39:497)
timeToPreviewShow: action.timestamp - state.interaction.started
state.interaction == null at the time of exception
state.interaction appears to be null at certain times on the eventLogging reducer.
In this case it happens when processing a PREVIEW_SHOW action, but I've seen it happen too when processing a ABANDON_END action.
I can't come up with steps to reproduce. Randomly flickering through links, waiting for some and not others, moving from link to link waiting for preview or after abandoning preview quickly... I don't know.
Effect on the feature
Everything works, but the logging breaks for that certain action. Followup interactions work.