boolOrNull method
Implementation
bool? boolOrNull(String key) {
final value = this[key];
if (value is bool) return value;
if (value is num) return value != 0;
switch (value?.toString().trim().toLowerCase()) {
case 'true':
case '1':
case 'yes':
return true;
case 'false':
case '0':
case 'no':
return false;
default:
return null;
}
}