Add 4th example

Author: tshemsedinov

JavaScript/4-hex.js

@@ -0,0 +1,15 @@
+'use strict';
+
+const fs = require('fs');
+
+const v8File = './3-file.dat';
+fs.readFile(v8File, (err, data) => {
+  console.log(
+    data
+      .toString('hex')
+      .toUpperCase()
+      .split('')
+      .map((c, i) => ((i % 2 !== 0) ? (c + ' ') : c))
+      .join('')
+  );
+});