node memory_warning ai_generated true

MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 listeners added

ID: node/memory-leak-warning

Also available as: JSON · Markdown
88%Fix Rate
90%Confidence
50Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
20 active — — —

Root Cause

Too many event listeners on one emitter. Usually forgetting to remove listeners.

generic

Workarounds

  1. 92% success Remove listeners when done: emitter.removeListener() or emitter.off() 
    emitter.removeListener() or emitter.off()

    Sources: https://nodejs.org/api/events.html#emitterremovelistenereventname-listener

  2. 88% success Use { once: true } for one-time listeners: emitter.on('event', fn, { once: true }) 
    true } for one-time listeners: emitter.on('event', fn, { once: true })

    Sources: https://nodejs.org/api/events.html#emitteroneventname-listener

  3. 90% success Check for listeners added in loops or repeated function calls 
    Check for listeners added in loops or repeated function calls

    Sources: https://nodejs.org/api/events.html

Dead Ends

Common approaches that don't work:

  1. Set maxListeners to Infinity 80% fail

    Hides the memory leak — listeners accumulate without bound

  2. Suppress the warning 85% fail

    The leak will grow until the process runs out of memory

Error Chain

Frequently confused with: