operator [] method
properties から、operator == の内容を自動更新できるようにするために定義している.
Implementation
Object operator [](String key) {
if(properties.containsKey(key)) return properties[key] as Object;
// for (var item in toMap().keys) {
// if(key == item) return toJson()[key] as Object;
// }
Result.panic(AggregationPatternErrorA(), Log(classLocation: AggregationPattern, functionLocation: '[] operator', monitor: {
'input key': key,
'valid keys': properties.keys,
}));
}