+ return exists(value) && validator.matches(value, new RegExp(`^[a-z0-9._]{${min},${max}}$`))
+}
+
+function isUserDisplayNameValid (value: string) {
+ return value === null || (exists(value) && validator.isLength(value, CONSTRAINTS_FIELDS.USERS.NAME))
+}
+
+function isUserDescriptionValid (value: string) {
+ return value === null || (exists(value) && validator.isLength(value, CONSTRAINTS_FIELDS.USERS.DESCRIPTION))