add RailwayTimeConversion method

Conversions/RailwayTimeConversion.js

@@ -0,0 +1,35 @@
+/*
+    The time conversion of normalized time to the railway is a simple algorithm 
+    because we know that if the time is in 'AM' value it means they only want 
+    some changes on hours and minutes and if the time in 'PM' it means the only 
+    want some changes in hour value.
+
+    Input Formate -> 07:05:45PM
+    Output Fromate -> 19:05:45
+
+    Problem & Explanation Source : https://www.mathsisfun.com/time.html
+*/
+
+/**
+ * RailwayTimeConversion method converts normalized time string to Railway time string.
+ * @param {String} timeString Normalized time string.
+ * @returns {String} Railway time string.
+ */
+const RailwayTimeConversion = (timeString) => {
+    // firstly, check that input is a string or not.
+    if (typeof timeString !== 'string') {
+        return new TypeError('Argument is not a string.')
+    }
+    // split the string by ':' character.
+    const [hour, minute, scondWithShift] = timeString.split(':')
+    // split second and shift value.
+    const [second, shift] = [scondWithShift.substr(0, 2), scondWithShift.substr(2)]
+    // convert shifted time to not-shift time(Railway time) by using the above explanation.
+    if (shift === 'PM') {
+        if (parseInt(hour) === 12) { return `${hour}:${minute}:${second}` } else { return `${parseInt(hour) + 12}:${minute}:${second}` }
+    } else {
+        if (parseInt(hour) === 12) { return `00:${minute}:${second}` } else { return `${hour}:${minute}:${second}` }
+    }
+}
+
+module.exports = RailwayTimeConversion