sendOnLeave throws a TypeError

[adriaandotcom]

sendOnLeave throws a TypeError: Illegal invocation on line 554:

nav.sendBeacon(fullApiUrl + "/append", stringify(append));

This is the relevant part of the code:

if (push || !nav.sendBeacon) {
    // sendData will assign payload to request
    sendData(append, undefinedVar, trueVar);
} else {
    nav.sendBeacon(fullApiUrl + "/append", stringify(append));
}

The error happens when nav.sendBeacon is invoked in the else block.

You might want to check if nav or sendBeacon is being called out of context or if there’s an issue with the scope.