From 47f86cc5b38768e100aa640c1a263f38f360a961 Mon Sep 17 00:00:00 2001
From: iseulde <wp@iseulde.com>
Date: Tue, 29 Jan 2019 16:54:04 +0100
Subject: [PATCH] Guard against negative lineIndex

---
 packages/rich-text/src/get-parent-line-index.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/rich-text/src/get-parent-line-index.js b/packages/rich-text/src/get-parent-line-index.js
index e7ca8dc3960214..bd3f72de965196 100644
--- a/packages/rich-text/src/get-parent-line-index.js
+++ b/packages/rich-text/src/get-parent-line-index.js
@@ -19,7 +19,7 @@ export function getParentLineIndex( { text, formats }, lineIndex ) {
 
 	let index = lineIndex;
 
-	while ( index-- ) {
+	while ( index-- >= 0 ) {
 		if ( text[ index ] !== LINE_SEPARATOR ) {
 			continue;
 		}