@fuckyep это из-за того это это строка
'{"ok":true,"result":[{"update_id":598272002,"message":{"message_id":1,"from":{"id":211428277,"is_bot":false,"first_name":".","username":"Exp1g"},"chat":{"id":211428277,"first_name":".","username":"Exp1g","type":"private"},"date":1593461502,"text":"/start","entities":[{"offset":0,"length":6,"type":"bot_command"}]}}]}'
а .result[0].message.date верно для объекта
{"ok":true,"result":[{"update_id":598272002,"message":{"message_id":1,"from":{"id":211428277,"is_bot":false,"first_name":".","username":"Exp1g"},"chat":{"id":211428277,"first_name":".","username":"Exp1g","type":"private"},"date":1593461502,"text":"/start","entities":[{"offset":0,"length":6,"type":"bot_command"}]}}]}
что бы строку в объект надо добавить JSON.parse()
( JSON.parse( [[TELEGRAM_MESSAGES]] ) ).result[0].message.date