fix some browsers (including firefox) downloading the script as a text file

src/infrastructure/SaveFileDialog.ts

@@ -1,9 +1,18 @@
 import fileSaver from 'file-saver';
 
+export enum FileType {
+    BatchFile,
+}
 export class SaveFileDialog {
-    public static saveText(text: string, fileName: string): void {
+    public static saveFile(text: string, fileName: string, type: FileType): void {
-        this.saveBlob(text, 'text/plain;charset=utf-8', fileName);
+        const mimeType = this.mimeTypes.get(type);
+        this.saveBlob(text, mimeType, fileName);
     }
+    private static readonly mimeTypes = new Map<FileType, string>([
+        // Some browsers (including firefox + IE) require right mime type
+        // otherwise they ignore extension and save the file as text.
+        [ FileType.BatchFile, 'application/bat' ], // https://en.wikipedia.org/wiki/Batch_file
+    ]);
 
     private static saveBlob(file: BlobPart, fileType: string, fileName: string): void {
         try {

src/presentation/TheCodeButtons.vue

@@ -16,7 +16,7 @@
 <script lang="ts">
 import { Component } from 'vue-property-decorator';
 import { StatefulVue } from './StatefulVue';
-import { SaveFileDialog } from './../infrastructure/SaveFileDialog';
+import { SaveFileDialog, FileType } from './../infrastructure/SaveFileDialog';
 import { Clipboard } from './../infrastructure/Clipboard';
 import IconButton from './IconButton.vue';
 
@@ -43,7 +43,7 @@ export default class TheCodeButtons extends StatefulVue {
 
   public async saveCodeAsync() {
       const state = await this.getCurrentStateAsync();
-      SaveFileDialog.saveText(state.code.current, 'privacy-script.bat');
+      SaveFileDialog.saveFile(state.code.current, 'privacy-script.bat', FileType.BatchFile);
   }
 }
 </script>