Added config file extension validation

src/cli/utils/CLIUtils.ts

@@ -1,6 +1,16 @@
+import * as path from 'path';
+
 import { TDictionary } from '../../types/TDictionary';
 
 export class CLIUtils {
+    /**
+     * @type {string[]}
+     */
+    public static readonly allowedConfigFileExtensions: string[] = [
+        '.js',
+        '.json'
+    ];
+
     /**
      * @param {string} configPath
      * @returns {TDictionary}
@@ -8,13 +18,20 @@ export class CLIUtils {
     public static getUserConfig (configPath: string): TDictionary {
         let config: TDictionary;
 
+        const configFileExtension: string = path.extname(configPath);
+        const isValidExtension: boolean = CLIUtils.allowedConfigFileExtensions.includes(configFileExtension);
+
+        if (!isValidExtension) {
+            throw new ReferenceError('Given config path must be a valid `.js` or `.json` file path');
+        }
+
         try {
             config = require(configPath);
         } catch {
             try {
                 config = __non_webpack_require__(configPath);
             } catch {
-                throw new ReferenceError('Given config path must be a valid `.js` or `.json` file path');
+                throw new ReferenceError(`Cannot open config file with path: ${configPath}`);
             }
         }