CLI class: added input file extension check

src/cli/JavaScriptObfuscatorCLI.ts

@@ -11,6 +11,13 @@ import { DEFAULT_PRESET } from "../preset-options/DefaultPreset";
 import { JavaScriptObfuscator } from "../JavaScriptObfuscator";
 
 export class JavaScriptObfuscatorCLI {
+    /**
+     * @type {string[]}
+     */
+    private static availableInputExtensions: string[] = [
+        '.js'
+    ];
+
     /**
      * @type {BufferEncoding}
      */
@@ -153,6 +160,10 @@ export class JavaScriptObfuscatorCLI {
             throw new ReferenceError(`First argument must be a valid file path`);
         }
 
+        if (JavaScriptObfuscatorCLI.availableInputExtensions.indexOf(path.extname(inputPath)) === -1) {
+            throw new ReferenceError(`Input file must have .js extension`);
+        }
+
         return inputPath;
     }