propsの宣言のvalueの謎の？(クエスチョンマーク)の意味
未解決
意味がわかりそうで分からない。
type A = { prop?: T } means that object can have prop of type T or do not have it at all.
type B = { prop: ?T } means that object always have prop, it can be of type T or null.
type C = { prop?: ?T } means that object can have prop, it can be of type T or null or do not have prop at all.