Challenge 18 complete, readme initialized.

nitishdayal · nitishdayal · commit 80f2f800dbbf · 2016-12-24T14:37:01.000-08:00
diff --git a/exercises/18 - Adding Up Times with Reduce/README.md b/exercises/18 - Adding Up Times with Reduce/README.md
@@ -0,0 +1,4 @@
+# Exercise 18: Adding Up Times With Reduce
+Nitish Dayal, Software & Applications Developer - [Contact](http://nitishdayal.me)  
+Last Commit Date: Dec 24, 2016
+
diff --git a/exercises/18 - Adding Up Times with Reduce/index-START.html b/exercises/18 - Adding Up Times with Reduce/index-START.html
diff --git a/exercises/18 - Adding Up Times with Reduce/index.html b/exercises/18 - Adding Up Times with Reduce/index.html
@@ -1,9 +1,11 @@
 <!DOCTYPE html>
 <html lang="en">
+
 <head>
   <meta charset="UTF-8">
   <title>Videos</title>
 </head>
+
 <body>
   <ul class="videos">
     <li data-time="5:43">
@@ -181,27 +183,48 @@
       Video 58
     </li>
 
-<script>
-
-  const timeNodes = Array.from(document.querySelectorAll('[data-time]'));
+    <script>
+      (() => {
+        // Hide all the list items because I don't want to see all that nonsense
+        // document.querySelectorAll('[data-time]').forEach(listItem => listItem.hidden = true)
 
-  const seconds = timeNodes
-    .map(node => node.dataset.time)
-    .map(timeCode => {
-      const [mins, secs] = timeCode.split(':').map(parseFloat);
-      return (mins * 60) + secs;
-    })
-    .reduce((total, vidSeconds) => total + vidSeconds);
+        // Declare a constant and define as an ARRAY of all items with a 'data-key'
+        // property (used spread operator to create array)
+        const allTimes = [...document.querySelectorAll('[data-time]')]
 
-    let secondsLeft = seconds;
-    const hours = Math.floor(secondsLeft / 3600);
-    secondsLeft = secondsLeft % 3600;
+        /** Declare a constant and define as the return value of mapping over each item
+          * in the array TWICE and reducing the result of those maps to a single numeric
+          * value.
+          */
+        const seconds = allTimes
+          .map(listItem => listItem.dataset.time) // Get the 'data-time' property
+          .map(timeValue => {
+            /** Declare constants minutes & seconds using array destructuring
+              * and define as the result of splitting the 'data-time' property
+              * a list item at ':' and parsing the returned two strings
+              * as float numbers
+              */
+            const [minutes, seconds] = timeValue.split(':').map(parseFloat)
+            return minutes * 60 + seconds // Return the total seconds
+          })
+          // Add up all the seconds
+          .reduce((runningTotal, seconds) => runningTotal + seconds)
 
-    const mins = Math.floor(secondsLeft / 60);
-    secondsLeft = secondsLeft % 60;
-
-    console.log(hours, mins, secondsLeft);
-
-</script>
+        /** Calculate hours by dividing total seconds by 3600 (seconds in a minute (60)
+          * multiplied by minutes in an hour (60)) and round the value DOWN before
+          * returning
+          */
+        const hours = Math.floor(seconds / 3600)
+        // Set variable to remainder of seconds after calculating hours
+        let secondsLeft = seconds % 3600
+        // Calculate remaining minutes
+        const minutes = Math.floor(secondsLeft / 60)
+        // Calculate remaining seconds
+        secondsLeft %= 60
+        // Log 'em out!
+        console.log(`Total video time: ${hours} hours, ${minutes} minutes, and ${secondsLeft} seconds`)
+      })();
+    </script>
 </body>
-</html>
+
+</html>
