From 6c32a39fe807f96e23794e1d7996a6063898a081 Mon Sep 17 00:00:00 2001
From: Jason Chen <jhchen7@gmail.com>
Date: Sun, 16 Apr 2017 20:27:37 -0700
Subject: [PATCH] fix #1339

---
 modules/keyboard.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/keyboard.js b/modules/keyboard.js
index 84cd836278..20cb270956 100644
--- a/modules/keyboard.js
+++ b/modules/keyboard.js
@@ -275,7 +275,7 @@ function handleBackspace(range, context) {
   if (range.index === 0 || this.quill.getLength() <= 1) return;
   let [line, ] = this.quill.getLine(range.index);
   let formats = {};
-  if (context.offset === 0) {
+  if (context.offset === 0 && line.prev != null && line.prev.length() > 1) {
     let curFormats = line.formats();
     let prevFormats = this.quill.getFormat(range.index-1, 1);
     formats = DeltaOp.attributes.diff(curFormats, prevFormats) || {};