Can we have a "insertFinalNewline" option in "FormattingOptions"? Fixes #11

Author: aeschli

CHANGELOG.md

@@ -1,3 +1,9 @@
+3.0.0 2020-11-13
+==================
+  * fixed API spec for `parseTree`. Can return `undefine` for empty input.
+  * added new API `FormattingOptions.insertFinalNewline`.
+
+
 2.3.0 2020-07-03
 ==================
   * new API `ModificationOptions.isArrayInsertion`: If `JSONPath` refers to an index of an array and `isArrayInsertion` is `true`, then `modify` will insert a new item at that location instead of overwriting its contents.

src/impl/format.ts

@@ -63,7 +63,7 @@ export function format(documentText: string, range: Range | undefined, options:
 	}
 	let editOperations: Edit[] = [];
 	function addEdit(text: string, startOffset: number, endOffset: number) {
-		if (!hasError && startOffset < rangeEnd && endOffset > rangeStart && documentText.substring(startOffset, endOffset) !== text) {
+		if (!hasError && (!range || (startOffset < rangeEnd && endOffset > rangeStart)) && documentText.substring(startOffset, endOffset) !== text) {
 			editOperations.push({ offset: startOffset, length: endOffset - startOffset, content: text });
 		}
 	}
@@ -155,7 +155,9 @@ export function format(documentText: string, range: Range | undefined, options:
 			if (lineBreak && (secondToken === SyntaxKind.LineCommentTrivia || secondToken === SyntaxKind.BlockCommentTrivia)) {
 				replaceContent = newLineAndIndent();
 			}
-
+		}
+		if (secondToken === SyntaxKind.EOF) {
+			replaceContent = options.insertFinalNewline ? eol : '';
 		}
 		let secondTokenStart = scanner.getTokenOffset() + formatTextStart;
 		addEdit(replaceContent, firstTokenEnd, secondTokenStart);

src/main.ts

@@ -321,6 +321,10 @@ export interface FormattingOptions {
 	 * The default 'end of line' character. If not set, '\n' is used as default.
 	 */
 	eol?: string;
+	/**
+	 * If set, will add a new line at the end of the document.
+	 */
+	insertFinalNewline?: boolean;
 }
 
 /**

src/test/format.test.ts

@@ -10,7 +10,7 @@ import { Range } from '../main';
 
 suite('JSON - formatter', () => {
 
-	function format(content: string, expected: string, insertSpaces = true) {
+	function format(content: string, expected: string, insertSpaces = true, insertFinalNewline = false) {
 		let range: Range | undefined = void 0;
 		var rangeStart = content.indexOf('|');
 		var rangeEnd = content.lastIndexOf('|');
@@ -19,7 +19,7 @@ suite('JSON - formatter', () => {
 			range = { offset: rangeStart, length: rangeEnd - rangeStart };
 		}
 
-		var edits = Formatter.format(content, range, { tabSize: 2, insertSpaces: insertSpaces, eol: '\n' });
+		var edits = Formatter.format(content, range, { tabSize: 2, insertSpaces, insertFinalNewline, eol: '\n' });
 
 		let lastEditOffset = content.length;
 		for (let i = edits.length - 1; i >= 0; i--) {
@@ -472,7 +472,7 @@ suite('JSON - formatter', () => {
 		format(content, expected);
 	});
 
-	test('line comment bug 33 ', () => {
+	test('line comment, enforce line comment ', () => {
 		var content = [
 			'{"settings": // This is some text',
 			'{',
@@ -504,4 +504,18 @@ suite('JSON - formatter', () => {
 
 		format(content, expected);
 	});
+
+	test('insertFinalNewline', () => {
+		var content = [
+			'{',
+			'}'
+		].join('\n');
+
+		var expected = [
+			'{}',
+			''
+		].join('\n');
+
+		format(content, expected, undefined, true);
+	});
 });