What is the ruling on swearing an oath while angry? Does it entail sin or expiation? And is it similar to divorce under duress of anger?

Anger has three degrees: The first is that it does not alter the intellect, in which case everything that issues from the person is binding. The second is that one completely loses consciousness, in which case nothing is binding upon him. The third is that it takes hold without removing the intellect, but it prevents one from intending what he says, and there is a difference of opinion regarding this. However, the evidence indicates that divorce and contracts do not occur in this state. If the anger falls into the last two degrees, then there is no breaking of an oath for the swearer, because it is considered a vain oath (laghw al-yameen), due to the Almighty's saying: "Allah will not impose blame upon you for what is unintentional in your oaths, but He will impose blame upon you for what your hearts have earned." (Al-Baqarah: 225), and "Allah will not impose blame upon you for what is unintentional in your oaths, but He will impose blame upon you for what you intended of oaths. So its expiation is the feeding of ten needy people from the average of that which you feed your [own] families or clothing them or freeing a slave. But whoever finds not [the means] - then a fast of three days." (Al-Ma'idah: 89). The ruling on swearing an oath while angry is like any other oath; there is no sin in it unless it is for an act of disobedience. A Muslim should avoid anger due to the Prophet's (peace and blessings be upon him) saying: "Do not get angry."