added path library for reliability

Author: nedjulius

src/assets/js/cache-busting.js

@@ -1,20 +1,22 @@
 module.exports.register = function(Handlebars, options) {
   Handlebars.registerHelper('versionedAsset', function(options) {
-    // requiring crypto library for hashing
+    // node libraries
     const crypto = require('crypto');
-    // retrieving full path to the asset from the handlebar helper context
-    const path = options.fn(this);
-    const hash = crypto.createHash('sha256');
+    const path = require('path');
     const fs = require('fs');
-    const ext = __dirname.substr(0, __dirname.length - 9).replace("/src", "/dist");
+    const filePath = options.fn(this);
+    const hash = crypto.createHash('sha256');
+    // creating full path from the root dir to the file
+    const fullPath = path.join(__dirname, "../../..", "dist", filePath);
     let hashCode = "";
     hash.on('readable', () => {
       const data = hash.read();
       if (data) hashCode = data.toString('hex');
     })
-    hash.write(fs.readFileSync(ext + path, function (err) { if (err) return 0 }).toString());
+    hash.write(fs.readFileSync(fullPath, function (err) { if (err) return 0 }).toString());
     hash.end();
-    hashCode = "/" + path + "?v=" + hashCode.substr(0, 6);
+    // creating a version string from first 6 hash characters
+    hashCode = filePath + "?v=" + hashCode.substr(0, 6);
     return hashCode;
   });
 };