Fix error with null rules list

clehner · Aug 7, 2015 · 6c6ab5e · 6c6ab5e
1 parent 74781e4
commit 6c6ab5e
Showing 1 changed file with 4 additions and 3 deletions.
diff --git a/lib/sheet.js b/lib/sheet.js
@@ -412,7 +412,8 @@ RulesList.prototype.toJSON = function() {
 RulesList.prototype.diff = Array.pool(function(rulesDiff, other) {
 	if (!other) return;
 	var skip = 0,
-		minLength = Math.min(this.rules.length, other.rules.length);
+		otherLength = other.rules ? other.rules.length : 0;
+		minLength = Math.min(this.rules.length, otherLength);
 
 	// handle changed and added rules
 	for (var i = 0; i < minLength; i++) {
@@ -440,14 +441,14 @@ RulesList.prototype.diff = Array.pool(function(rulesDiff, other) {
 		}
 	}
 
-	if (i < other.rules.length) {
+	if (i < otherLength) {
 		//console.log('push more', skip, theirRules.slice(i));
 		if (skip) {
 			rulesDiff.push({
 				skip: skip
 			});
 		}
-		for (; i < other.rules.length; i++) {
+		for (; i < otherLength; i++) {
 			rulesDiff.push(other.rules[i].toJSON());
 		}
 	} else if (i < this.rules.length) {