Add lighweight immutable datetime abstraction.

src/uxbox/util/datetime.cljs

@@ -0,0 +1,102 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+;;
+;; Copyright (c) 2015-2016 Andrey Antukh <niwi@niwi.nz>
+
+(ns uxbox.util.datetime
+  (:require [cljsjs.moment]))
+
+;; A simplified immutable date time representation type.
+
+(deftype DateTime [^number v]
+  IComparable
+  (-compare [this other]
+    (if (instance? DateTime other)
+      (compare v (.-v other))
+      (throw (js/Error. (str "Cannot compare " this " to " other)))))
+
+  IPrintWithWriter
+  (-pr-writer [_ writer _]
+    (let [m (js/moment v)
+          ms (.toISOString m)]
+      (-write writer (str "#datetime \"" ms "\""))))
+
+  Object
+  (toString [this]
+    (let [m (js/moment v)]
+      (.toISOString m)))
+
+  (equiv [this other]
+    (-equiv this other))
+
+  IHash
+  (-hash [_] v))
+
+(alter-meta! #'->DateTime assoc :private true)
+
+(defn datetime
+  "Create a new DateTime instance from
+  unix offset."
+  [v]
+  {:pre [(number? v)]}
+  (DateTime. v))
+
+(defn datetime?
+  "Return true if `v` is an instance of DateTime."
+  [v]
+  (instance? DateTime v))
+
+(defn parse
+  "Parse a string representation of datetime
+  with an optional `format` parameter."
+  ([v] (parse v :offset))
+  ([v fmt]
+   (cond
+     (datetime? v) v
+     (= fmt :offset) (DateTime. v)
+     :else (let [m (if (= fmt :unix)
+                     (js/moment.unix v)
+                     (js/moment v fmt))]
+             (DateTime. (.valueOf m))))))
+
+(defn format
+  "Returns a string representation of the DateTime
+  instance with optional `fmt` format parameter.
+
+  You can use `:iso` and `:unix` shortcuts as
+  format parameter.
+
+  You can read more about format tokens here:
+  http://momentjs.com/docs/#/displaying/format/
+  "
+  ([v] (format v :iso))
+  ([v fmt]
+   (let [vm (js/moment v)]
+     (case fmt
+       :unix (.unix vm)
+       :offset (.valueOf v)
+       :iso (.toISOString vm)
+       (.format vm fmt)))))
+
+(defn now
+  "Return the current DateTime."
+  []
+  (let [vm (js/moment)]
+    (DateTime. (.valueOf vm))))
+
+(defn timeago
+  [v]
+  (let [dt (parse v)
+        vm (js/moment (.-v dt))]
+    (.fromNow vm)))
+
+;; (defn day
+;;   [v]
+;;   (let [dt (parse v)
+;;         vm (js/moment (.-v dt))
+;;         fmt #js {:sameDay "[Today]"
+;;                  :sameElse "[Today]"
+;;                  :lastDay "[Yesterday]"
+;;                  :lastWeek "[Last] dddd"}]
+;;     (.calendar vm nil fmt)))