Group all facts from a history DB for an entity in Datomic by transaction, using sorted map to order.

e_tx_history.clj

(require '[datomic.api :as d])

;; for a particular entity, find it's entire tx history
(defn e->tx-history [db ent-id]
  (->> (d/datoms (d/history db) :eavt ent-id)
       (map (fn [[e a v tx assert]]
              [e
               (-> db (d/pull '[:db/ident] a) :db/ident)
               v
               tx
               assert]))
       (group-by #(nth % 3))
       (into (sorted-map))))