library · inferred from evidence
EventEmitter
A core Node.js module for handling events, referenced here as part of the bug context.
- customerio-node: ERR_INVALID_ARG_TYPE: The listener argument must be of type Function on track()
This was a bug in the library itself: the track request pipeline passed a non-function where Node's EventEmitter expected a listener. The maintainer reproduced it, shipped the fix in `customerio-node v3.0.3` (tested first as 3.0.3-beta.1),