1 files changed, 4 insertions, 0 deletions
diff --git a/src/utility.js b/src/utility.js
index d5583ffb..2cc2408c 100644
--- a/src/utility.js
+++ b/src/utility.js
@@ -213,3 +213,7 @@ function setIntersect(x, y) {
   return ret;
 }
 
+function isNumber(x) {
+  return x == parseInt(x);
+}
+