feat: add support for files.insertFinalNewline during formatOnSave

packages/filesystem/src/browser/filesystem-preferences.ts

@@ -96,6 +96,12 @@ export const filesystemPreferenceSchema: PreferenceSchema = {
             description: nls.localizeByDefault('When enabled, will trim trailing whitespace when saving a file.'),
             scope: 'language-overridable'
         },
+        'files.insertFinalNewline': {
+            type: 'boolean',
+            default: false,
+            description: nls.localizeByDefault('When enabled, insert a final new line at the end of the file when saving it.'),
+            scope: 'language-overridable'
+        },
         'files.maxConcurrentUploads': {
             type: 'integer',
             default: 1,
@@ -117,6 +123,7 @@ export interface FileSystemConfiguration {
     'files.participants.timeout': number
     'files.maxFileSizeMB': number
     'files.trimTrailingWhitespace': boolean
+    'files.insertFinalNewline': boolean
     'files.maxConcurrentUploads': number
 }
 

packages/monaco/src/browser/monaco-editor-provider.ts

@@ -268,6 +268,10 @@ export class MonacoEditorProvider {
         if (shouldRemoveWhiteSpace) {
             await editor.runAction('editor.action.trimTrailingWhitespace');
         }
+        const insertFinalNewline = this.filePreferences.get({ preferenceName: 'files.insertFinalNewline', overrideIdentifier }, undefined, uri);
+        if (insertFinalNewline) {
+            this.insertFinalNewline(editor);
+        }
         return [];
     }
 
@@ -452,4 +456,33 @@ export class MonacoEditorProvider {
             )
         ) as MonacoDiffEditor;
     }
+
+    protected insertFinalNewline(editor: MonacoEditor): void {
+        const model = editor.document && editor.document.textEditorModel;
+        if (!model) {
+            return;
+        }
+
+        const lines = model?.getLineCount();
+        if (lines === 0) {
+            return;
+        }
+
+        const lastLine = model?.getLineContent(lines);
+        if (lastLine.trim() === '') {
+            return;
+        }
+
+        const lastLineMaxColumn = model?.getLineMaxColumn(lines);
+        const range = {
+            startLineNumber: lines,
+            startColumn: lastLineMaxColumn,
+            endLineNumber: lines,
+            endColumn: lastLineMaxColumn
+        };
+        model?.applyEdits([{
+            range,
+            text: model?.getEOL()
+        }]);
+    }
 }