Fix TypeError in requestMetaData when n2kOut is not available#307
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dirkwa wants to merge 1 commit intoSignalK:masterfrom
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Fix TypeError in requestMetaData when n2kOut is not available#307dirkwa wants to merge 1 commit intoSignalK:masterfrom
dirkwa wants to merge 1 commit intoSignalK:masterfrom
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requestMetaData() calls this.n2kListener.emit() but n2kListener is only set when n2kOutIsAvailable() is called. If a device changes its N2K source address (PGN 60928 with a different CAN name) before n2kOut becomes available, toDelta() calls requestMetaData() and crashes with: TypeError: Cannot read properties of undefined (reading 'emit') Add a guard to return early if n2kListener is not yet initialized.
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Summary
requestMetaData()crashes withTypeError: Cannot read properties of undefined (reading 'emit')whenthis.n2kListeneris not yet initializedn2kOutIsAvailable()has been calledn2kListeneris not setHow to reproduce
On a CAN bus with many devices, an address claim conflict can cause a device to change its source address. When this happens before NMEA2000 output is available,
toDelta()callsrequestMetaData()which crashes:Fix
Guard
requestMetaData()to return early (with a resolved promise) whenn2kListeneris undefined, instead of crashing. The metadata request will simply be skipped — oncen2kOutIsAvailable()is eventually called,requestAllMeta()will request metadata for all known sources anyway.