Implemented weekdayRange function

Author: utsavkesharwani

test/weekdayRange.js

@@ -5,17 +5,41 @@
 
 var assert = require('assert');
 var weekdayRange = require('../weekdayRange');
+var vanillaGetUTCDay = Date.prototype.getUTCDay;
+var vanillaGetDay = Date.prototype.getDay;
 
-describe('weekdayRange(wd1, wd2, gmt)', function () {
+describe('hooks', function() {
 
-  var tests = [
-  ];
+  before(function() {
+    Date.prototype.getDay    = function() { return 6; } // Setting local weekday as SAT(6)
+    Date.prototype.getUTCDay = function() { return 5; } // Setting UTC weekday as FRI(5)
+  });
 
-  tests.forEach(function (test) {
-    var expected = test.pop();
-    it('should return `' + expected +'` for "' + test.join('", "') + '"', function () {
-      assert.equal(expected, weekdayRange(test[0], test[1], test[2]));
-    });
+  after(function() {
+    Date.prototype.getUTCDay = vanillaGetUTCDay;
+    Date.prototype.getDay    = vanillaGetDay;
   });
 
+  describe('weekdayRange(wd1, wd2, gmt)', function () {
+
+    var tests = [
+      ["MON", "FRI", false],
+      ["MON", "FRI", "GMT", true],
+      ["SAT", true],
+      ["SAT", "GMT", false],
+      ["FRI", "MON", true],
+      ["SAT", "MON", "GMT", false],
+      ["SOME", "RANDOM", false],
+      ["RANDOM", false],
+      ["RANDOM", "VALUE", "IST", false],
+    ];
+
+    tests.forEach(function (test) {
+      var expected = test.pop();
+      it('should return `' + expected +'` for "' + test.join('", "') + '"', function () {
+        assert.equal(expected, weekdayRange(test[0], test[1], test[2]));
+      });
+    });
+
+  });
 });

weekdayRange.js

@@ -48,7 +48,33 @@ module.exports = weekdayRange;
  * @return {Boolean}
  */
 
+const dayOrder = { "SUN": 0, "MON": 1, "TUE": 2, "WED": 3, "THU": 4, "FRI": 5, "SAT": 6 };
+
 function weekdayRange (wd1, wd2, gmt) {
-  // TODO: implement me!
-  return false;
+
+  var useGMTzone = (wd2 == "GMT" || gmt == "GMT"),
+      todaysDay  = getTodaysDay(useGMTzone),
+      wd1Index   = dayOrder[wd1] || -1,
+      wd2Index   = dayOrder[wd2] || -1,
+      result     = false;
+
+  if (wd2Index < 0) {
+    result = (todaysDay == wd1Index);
+  } else {
+    if (wd1Index <= wd2Index) {
+      result = valueInRange(wd1Index, todaysDay, wd2Index);
+    } else {
+      result = valueInRange(wd1Index, todaysDay, 6) || valueInRange(0, todaysDay, wd2Index);
+    }
+  }
+  return result;
+}
+
+function getTodaysDay (gmt) {
+  return (gmt ? (new Date()).getUTCDay() : (new Date()).getDay());
+}
+
+// start <= value <= finish
+function valueInRange (start, value, finish) {
+  return (start <= value) && (value <= finish);
 }