Data commit

Task/Last-Friday-of-each-month/JavaScript/last-friday-of-each-month-1.js

@@ -0,0 +1,28 @@
+var last_friday_of_month, print_last_fridays_of_month;
+
+last_friday_of_month = function(year, month) {
+  var i, last_day;
+  i = 0;
+  while (true) {
+    last_day = new Date(year, month, i);
+    if (last_day.getDay() === 5) {
+      return last_day.toDateString();
+    }
+    i -= 1;
+  }
+};
+
+print_last_fridays_of_month = function(year) {
+  var month, results;
+  results = [];
+  for (month = 1; month <= 12; ++month) {
+    results.push(console.log(last_friday_of_month(year, month)));
+  }
+  return results;
+};
+
+(function() {
+  var year;
+  year = parseInt(process.argv[2]);
+  return print_last_fridays_of_month(year);
+})();

Task/Last-Friday-of-each-month/JavaScript/last-friday-of-each-month-2.js

@@ -0,0 +1,71 @@
+(function () {
+    'use strict';
+
+    // lastFridaysOfYear :: Int -> [Date]
+    function lastFridaysOfYear(y) {
+        return lastWeekDaysOfYear(y, days.friday);
+    }
+
+    // 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(lastFridaysOfYear)
+        )
+        .map(function (row) {
+            return row
+                .map(isoDateString)
+                .join('\t');
+        })
+        .join('\n');
+})();

Task/Last-Friday-of-each-month/JavaScript/last-friday-of-each-month-3.js

@@ -0,0 +1,80 @@
+(() => {
+    "use strict";
+
+    // ------------ LAST FRIDAY OF EACH MONTH ------------
+
+    // lastWeekDaysOfYear :: Int -> Int -> [Date]
+    const lastWeekDaysOfYear = iWeekDay =>
+        y => {
+            const isLeap = n => (
+                (0 === n % 4) && (0 !== n % 100)) || (
+                0 === y % 400
+            );
+
+            return [
+                    31, isLeap(y) ? 29 : 28,
+                    31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+                ]
+                .map((d, m) =>
+                    new Date(Date.UTC(
+                        y, m, d - ((
+                            new Date(Date.UTC(
+                                y, m, d
+                            ))
+                            .getDay() + (7 - iWeekDay)
+                        ) % 7)
+                    ))
+                );
+        };
+
+
+    const days = {
+        sunday: 0,
+        monday: 1,
+        tuesday: 2,
+        wednesday: 3,
+        thursday: 4,
+        friday: 5,
+        saturday: 6
+    };
+
+    // ---------------------- TEST -----------------------
+    const main = () =>
+        transpose(
+            enumFromTo(2015)(2019)
+            .map(lastWeekDaysOfYear(days.friday))
+        )
+        .map(
+            row => row.map(isoDateString).join("\t")
+        )
+        .join("\n");
+
+
+    // ---------------- GENERIC FUNCTIONS ----------------
+
+    // enumFromTo :: Int -> Int -> [Int]
+    const enumFromTo = m =>
+        n => Array.from({
+            length: 1 + n - m
+        }, (_, i) => m + i);
+
+
+    // isoDateString :: Date -> String
+    const isoDateString = dte =>
+        dte.toISOString()
+        .substr(0, 10);
+
+
+    // transpose :: [[a]] -> [[a]]
+    const transpose = rows =>
+        // The columns of the input transposed
+        // into new rows.
+        0 < rows.length ? rows[0].map(
+            (x, i) => rows.flatMap(
+                v => v[i]
+            )
+        ) : [];
+
+    // MAIN ---
+    return main();
+})();