Most Frequent Weekdays

most-frequent-weekdays/index.js

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+// https://www.codewars.com/kata/56eb16655250549e4b0013f4/javascript
+
+function mostFrequentDays(year) {
+  const weekdays = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday'];
+  const ds = new Date(year, 0, 1, 0, 0, 0, 0);
+  const de1 = new Date(year, 0, 365, 0, 0, 0, 0);
+  const de2 = new Date(year, 0, 366, 0, 0, 0, 0);
+  const de = de2.getFullYear() === year ? de2 : de1;
+  const freq = [];
+  for (let i = ds.getDay();1; ++i) {
+    freq.push((i+6)%7);
+    if (i % 7 === de.getDay()) {
+      break;
+    }
+  }
+  return freq.sort((a, b) => a-b).map(w => weekdays[w]);
+}