From f8be9e71032b0c279ad8170e8b5ad10c88fe31d2 Mon Sep 17 00:00:00 2001
From: Fang Lu <cc2lufang@gmail.com>
Date: Mon, 30 Oct 2017 18:06:28 -0500
Subject: [PATCH] Fix update message

Don't show update message for first-time loading
---
 node_modules/catalog.js | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/node_modules/catalog.js b/node_modules/catalog.js
index abe440b..a859e0f 100644
--- a/node_modules/catalog.js
+++ b/node_modules/catalog.js
@@ -77,17 +77,19 @@ Catalog.prototype.update = function(code) {
 			}
 
 			var newcrns = [];
-			for (var type in course.sections) {
-				course.sections[type].forEach((section) => {
-					var idx = oldcrns.indexOf(section.crn);
-					if (idx == -1) {
-						newcrns.push(section.crn);
-					} else {
-						oldcrns.splice(idx, 1);
-					}
-					this.sections[section.crn] = section;
-					section.course = course;
-				});
+			if (oldcrns.length != 0) {
+				for (var type in course.sections) {
+					course.sections[type].forEach((section) => {
+						var idx = oldcrns.indexOf(section.crn);
+						if (idx == -1) {
+							newcrns.push(section.crn);
+						} else {
+							oldcrns.splice(idx, 1);
+						}
+						this.sections[section.crn] = section;
+						section.course = course;
+					});
+				}
 			}
 			resolve({course: course, added: newcrns, removed: oldcrns});
 		}).bind(this), (err) => {