From 390089511b476c1e409ed2519e66f0140713807f Mon Sep 17 00:00:00 2001
From: Eemeli Aro <eemeli@gmail.com>
Date: Sat, 9 May 2020 07:05:27 +0300
Subject: [PATCH] Also indent top-level scalars with lines starting with %
 directives (#162)

---
 src/stringify/stringifyString.js | 4 +++-
 tests/doc/stringify.js           | 6 ++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/stringify/stringifyString.js b/src/stringify/stringifyString.js
index d98d826a..c7750c0f 100644
--- a/src/stringify/stringifyString.js
+++ b/src/stringify/stringifyString.js
@@ -14,7 +14,9 @@ const getFoldOptions = ({ indentAtStart }) =>
     ? Object.assign({ indentAtStart }, strOptions.fold)
     : strOptions.fold
 
-const containsDocumentMarker = str => /^(---|\.\.\.)/m.test(str)
+// Also checks for lines starting with %, as parsing the output as YAML 1.1 will
+// presume that's starting a new document.
+const containsDocumentMarker = str => /^(%|---|\.\.\.)/m.test(str)
 
 function lineLengthOverLimit(str, limit) {
   const strLen = str.length
diff --git a/tests/doc/stringify.js b/tests/doc/stringify.js
index 94e13172..1e797419 100644
--- a/tests/doc/stringify.js
+++ b/tests/doc/stringify.js
@@ -671,4 +671,10 @@ describe('Document markers in top-level scalars', () => {
     expect(str).toBe('"foo\n\n  ..."\n')
     expect(YAML.parse(str)).toBe('foo\n...')
   })
+
+  test('foo\\n%bar\\n', () => {
+    const str = YAML.stringify('foo\n%bar\n')
+    expect(str).toBe('|\n  foo\n  %bar\n')
+    expect(YAML.parse(str)).toBe('foo\n%bar\n')
+  })
 })