Move last-day-of-month? to date

Author: strika

src/commands/schedule_tasks.janet

@@ -17,10 +17,6 @@
 (defn- remove-year [formatted-date]
   (string/join (drop 1 (string/split "-" formatted-date)) "-"))
 
-(defn- last-day-of-month? [date]
-  (def tomorrow (date/+days date 1))
-  (not= (date :month) (tomorrow :month)))
-
 # Public
 (defn scheduled-for? [task date]
   (def formatted-date (date/format date true))
@@ -32,7 +28,7 @@
                               (index-of (date :month) [1 4 7 10]))
         (string "every year on " (remove-year formatted-date)) true
         (string "on " formatted-date) true
-        "every last day" (last-day-of-month? date)))
+        "every last day" (date/last-day-of-month? date)))
 
 (defn- missed-on-day [plan task date]
   (find (fn [day] (and (scheduled-for? task (day :date))

src/date.janet

@@ -86,6 +86,17 @@
       :day (+ (today :month-day) 1)
       :week-day (week-day-string (today :week-day))}))
 
+(defn +days [date n]
+  (def new-date-time (+ (to-time date) (* n seconds-in-day)))
+  (from-os-date-struct (os/date new-date-time)))
+
+(defn -days [date n]
+  (def new-date-time (- (to-time date) (* n seconds-in-day)))
+  (from-os-date-struct (os/date new-date-time)))
+
+(defn days-from-now [n]
+  (+days (today) n))
+
 (defn equal?
   [d1 d2]
   (= (to-time d1) (to-time d2)))
@@ -112,13 +123,10 @@
  [d1 d2]
  (>= (to-time d1) (to-time d2)))
 
-(defn +days [date n]
-  (def new-date-time (+ (to-time date) (* n seconds-in-day)))
-  (from-os-date-struct (os/date new-date-time)))
-
-(defn -days [date n]
-  (def new-date-time (- (to-time date) (* n seconds-in-day)))
-  (from-os-date-struct (os/date new-date-time)))
-
-(defn days-from-now [n]
-  (+days (today) n))
+(defn last-day-of-month?
+  ```
+  Returns true if date is the last day of a month.
+  ```
+  [date]
+  (def tomorrow (+days date 1))
+  (not= (date :month) (tomorrow :month)))

test/date_test.janet

@@ -68,6 +68,26 @@
   (is (d/after-or-eq? (d/date 2021 7 1) (d/date 2021 7 1)))
   (is (not (d/after-or-eq? (d/date 2021 7 1) (d/date 2021 7 15)))))
 
+## ————————————————————————————————————————————————————————————————————————————————————————————————
+## Test last-day-of-month?
+
+(deftest last-day-of-month?
+  (is (d/last-day-of-month? (d/date 2022 1 31)))
+  (is (d/last-day-of-month? (d/date 2022 2 28)))
+  (is (d/last-day-of-month? (d/date 2022 3 31)))
+  (is (d/last-day-of-month? (d/date 2022 4 30)))
+  (is (d/last-day-of-month? (d/date 2022 5 31)))
+  (is (d/last-day-of-month? (d/date 2022 6 30)))
+  (is (d/last-day-of-month? (d/date 2022 7 31)))
+  (is (d/last-day-of-month? (d/date 2022 8 31)))
+  (is (d/last-day-of-month? (d/date 2022 9 30)))
+  (is (d/last-day-of-month? (d/date 2022 10 31)))
+  (is (d/last-day-of-month? (d/date 2022 11 30)))
+  (is (d/last-day-of-month? (d/date 2022 12 31)))
+  (is (d/last-day-of-month? (d/date 2023 1 31)))
+  (is (not (d/last-day-of-month? (d/date 2022 1 30)))))
+
+
 ## ————————————————————————————————————————————————————————————————————————————————————————————————
 ## Test +days