Add comments for filename check

Author: astronomersiva

lib/utils/filename-normaliser.js

@@ -6,8 +6,12 @@ const { existsSync } = require('fs');
 
 const pkg = require(findup.sync('package.json'));
 
-const normaliseFileName = (fileName = '') => {
-  // not a valid file name
+const normaliseFileName = function(fileName = '') {
+  // check for invalid file paths
+  // for example,
+  // path.basename('myfile') will be myfile, doesn't need normalisation as this is probably
+  // not a template file
+  // path.basename('templates/myfile') will not be equal to fileName
   if (path.basename(fileName) === fileName) {
     return null;
   }
@@ -42,7 +46,7 @@ const normaliseFileName = (fileName = '') => {
   return path.join(...fileNameElements);
 };
 
-const getNormalisedFileName = (fileName, line = 1, column = 1) => {
+const getNormalisedFileName = function(fileName, line = 1, column = 1) {
   let normalisedFileName = normaliseFileName(fileName);
   if (existsSync(normalisedFileName)) {
     return `${normalisedFileName}:${line}:${column}`;