Data commit

Task/Find-the-last-Sunday-of-each-month/JavaScript/find-the-last-sunday-of-each-month-1.js

@@ -0,0 +1,16 @@
+function lastSundayOfEachMonths(year) {
+	var lastDay = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
+	var sundays = [];
+	var date, month;
+	if (year % 4 === 0 && (year % 100 !== 0 || year % 400 === 0)) {
+		lastDay[2] = 29;
+	}
+	for (date = new Date(), month = 0; month < 12; month += 1) {
+		date.setFullYear(year, month, lastDay[month]);
+		date.setDate(date.getDate() - date.getDay());
+		sundays.push(date.toISOString().substring(0, 10));
+	}
+	return sundays;
+}
+
+console.log(lastSundayOfEachMonths(2013).join('\n'));

Task/Find-the-last-Sunday-of-each-month/JavaScript/find-the-last-sunday-of-each-month-2.js

@@ -0,0 +1,73 @@
+(function () {
+    'use strict';
+
+    // lastSundaysOfYear :: Int -> [Date]
+    function lastSundaysOfYear(y) {
+        return lastWeekDaysOfYear(y, days.sunday);
+    }
+
+    // lastWeekDaysOfYear :: Int -> Int -> [Date]
+    function lastWeekDaysOfYear(y, iWeekDay) {
+        return [
+                31,
+                0 === y % 4 && 0 !== y % 100 || 0 === y % 400 ? 29 : 28,
+                31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+            ]
+            .map(function (d, m) {
+                var dte = new Date(Date.UTC(y, m, d));
+
+                return new Date(Date.UTC(
+                    y, m, d - (
+                        (dte.getDay() + (7 - iWeekDay)) % 7
+                    )
+                ));
+            });
+    }
+
+    // isoDateString :: Date -> String
+    function isoDateString(dte) {
+        return dte.toISOString()
+            .substr(0, 10);
+    }
+
+    // range :: Int -> Int -> [Int]
+    function range(m, n) {
+        return Array.apply(null, Array(n - m + 1))
+            .map(function (x, i) {
+                return m + i;
+            });
+    }
+
+    // transpose :: [[a]] -> [[a]]
+    function transpose(lst) {
+        return lst[0].map(function (_, iCol) {
+            return lst.map(function (row) {
+                return row[iCol];
+            });
+        });
+    }
+
+    var days = {
+        sunday: 0,
+        monday: 1,
+        tuesday: 2,
+        wednesday: 3,
+        thursday: 4,
+        friday: 5,
+        saturday: 6
+    }
+
+    // TEST
+
+    return transpose(
+            range(2012, 2016)
+            .map(lastSundaysOfYear)
+        )
+        .map(function (row) {
+            return row
+                .map(isoDateString)
+                .join('\t');
+        })
+        .join('\n');
+
+})();

Task/Find-the-last-Sunday-of-each-month/JavaScript/find-the-last-sunday-of-each-month-3.js

@@ -0,0 +1,106 @@
+(() => {
+    'use strict'
+
+    // MAIN -----------------------------------------------
+    // main :: IO ()
+    const main = () =>
+        console.log(unlines(
+            map(
+                compose(
+                    intercalate('\t'),
+                    map(isoDateString)
+                )
+            )(
+                transpose(
+                    map(lastWeekDaysOfYear(days.sunday))(
+                        enumFromTo(2019)(2022)
+                    )
+                )
+            )
+        ));
+
+    // WEEKDAYS -------------------------------------------
+
+    // lastWeekDaysOfYear :: Int -> Int -> [Date]
+    const lastWeekDaysOfYear = iWeekDay =>
+        y => map((d, m) =>
+            new Date(Date.UTC(
+                y, m, d - ((new Date(Date.UTC(y, m, d))
+                    .getDay() + (7 - iWeekDay)) % 7))))([
+            31,
+            0 === y % 4 && 0 !== y % 100 || 0 === y % 400 ? 29 : 28,
+            31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+        ]);
+
+    const days = {
+        sunday: 0,
+        monday: 1,
+        tuesday: 2,
+        wednesday: 3,
+        thursday: 4,
+        friday: 5,
+        saturday: 6
+    };
+
+    // GENERIC FUNCTIONS-----------------------------------
+
+    // compose (<<<) :: (b -> c) -> (a -> b) -> a -> c
+    const compose = (...fs) =>
+        x => fs.reduceRight((a, f) => f(a), x);
+
+    // enumFromTo :: Int -> Int -> [Int]
+    const enumFromTo = m => n =>
+        Array.from({
+            length: 1 + n - m
+        }, (_, i) => m + i);
+
+    // intercalate :: String -> [String] -> String
+    const intercalate = s => xs =>
+        xs.join(s);
+
+    // isoDateString :: Date -> String
+    const isoDateString = dte =>
+        dte.toISOString()
+        .substr(0, 10);
+
+    // map :: (a -> b) -> [a] -> [b]
+    const map = f => xs =>
+        (Array.isArray(xs) ? (
+            xs
+        ) : xs.split('')).map(f);
+
+    // If some of the rows are shorter than the following rows,
+    // their elements are skipped:
+    // > transpose [[10,11],[20],[],[30,31,32]] == [[10,20,30],[11,31],[32]]
+
+    // transpose :: [[a]] -> [[a]]
+    const transpose = xss => {
+        const go = xss =>
+            0 < xss.length ? (() => {
+                const
+                    h = xss[0],
+                    t = xss.slice(1);
+                return 0 < h.length ? (
+                    [
+                        [h[0]].concat(t.reduce(
+                            (a, xs) => a.concat(
+                                0 < xs.length ? (
+                                    [xs[0]]
+                                ) : []
+                            ),
+                            []
+                        ))
+                    ].concat(go([h.slice(1)].concat(
+                        t.map(xs => xs.slice(1))
+                    )))
+                ) : go(t);
+            })() : [];
+        return go(xss);
+    };
+
+    // unlines :: [String] -> String
+    const unlines = xs => xs.join('\n');
+
+    // MAIN ---
+    return main();
+})();