Initial data commit

Task/Date-manipulation/JavaScript/date-manipulation.js

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+function add12hours(dateString) {
+
+  // Get the parts of the date string
+  var parts = dateString.split(/\s+/),
+      date  = parts[1],
+      month = parts[0],
+      year  = parts[2],
+      time  = parts[3];
+
+  var hr    = Number(time.split(':')[0]),
+      min   = Number(time.split(':')[1].replace(/\D/g,'')),
+      ampm  = time && time.match(/[a-z]+$/i)[0],
+      zone  = parts[4].toUpperCase();
+
+  var months = ['January','February','March','April','May','June',
+                'July','August','September','October','November','December'];
+  var zones  = {'EST': 300, 'AEST': -600}; // Minutes to add to zone time to get UTC
+
+  // Convert month name to number, zero indexed. Return if invalid month
+  month = months.indexOf(month);
+  if (month === -1) { return; }
+
+  // Add 12 hours as specified. Add another 12 if pm for 24hr time
+  hr += (ampm.toLowerCase() === 'pm') ? 24 : 12
+
+  // Create a date object in local zone
+  var localTime = new Date(year, month, date);
+  localTime.setHours(hr, min, 0, 0);
+
+  // Adjust localTime minutes for the time zones so it is now a local date
+  // representing the same moment as the source date plus 12 hours
+  localTime.setMinutes(localTime.getMinutes() + zones[zone] - localTime.getTimezoneOffset() );
+  return localTime;
+}
+
+var inputDateString = 'March 7 2009 7:30pm EST';
+
+console.log(
+  'Input: ' + inputDateString + '\n' +
+  '+12hrs in local time: ' + add12hours(inputDateString)
+ );