From 6cd5c2b8462c0c7a4ce898125a2fc7e0507fabc6 Mon Sep 17 00:00:00 2001
From: Daniel Imms <daimms@microsoft.com>
Date: Tue, 31 Jan 2017 21:02:55 -0800
Subject: [PATCH] Add null checks in eraseRight and eraseLeft

Fixes #519
---
 src/xterm.js | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/src/xterm.js b/src/xterm.js
index f88c9452..ec4927c7 100644
--- a/src/xterm.js
+++ b/src/xterm.js
@@ -2159,14 +2159,14 @@ Terminal.prototype.nextStop = function(x) {
  * @param {number} y The line in which to operate.
  */
 Terminal.prototype.eraseRight = function(x, y) {
-  var line = this.lines.get(this.ybase + y)
-  , ch = [this.eraseAttr(), ' ', 1]; // xterm
-
-
+  var line = this.lines.get(this.ybase + y);
+  if (!line) {
+    return;
+  }
+  var ch = [this.eraseAttr(), ' ', 1]; // xterm
   for (; x < this.cols; x++) {
     line[x] = ch;
   }
-
   this.updateRange(y);
 };
 
@@ -2178,12 +2178,15 @@ Terminal.prototype.eraseRight = function(x, y) {
  * @param {number} y The line in which to operate.
  */
 Terminal.prototype.eraseLeft = function(x, y) {
-  var line = this.lines.get(this.ybase + y)
-  , ch = [this.eraseAttr(), ' ', 1]; // xterm
-
+  var line = this.lines.get(this.ybase + y);
+  if (!line) {
+    return;
+  }
+  var ch = [this.eraseAttr(), ' ', 1]; // xterm
   x++;
-  while (x--) line[x] = ch;
-
+  while (x--) {
+    line[x] = ch;
+  }
   this.updateRange(y);
 };