Not accurate. The consistution has been amended since 1991 to modify this and recognize that mainland China is legitimately ruled by another government. There is no more take back the mainland from the communist bandits.
Yet, interestingly, to the extent that the ROC says China is part of their territory (although under a different governmental jurisdiction at this time) what ostensibly will make the communists attack is that taiwan wants to officially say they are not the legitimate government of all China and don't want to be.
It's crazy. A country says they will attack another country if that country stops saying they want to take it over.
usually that means a peace treaty. The communists want war because Taiwan says they don't want war. But if Taiwan said they will take back the mainland from the communist bandits, the communist bandits are happy.
The communist's whole policy and threat is that they will attack taiwan if Taiwan says we don't want to attack you and destroy your regime and take over your land.