From 9fce4d40d04af8d75541897b5f437a495688b6bf Mon Sep 17 00:00:00 2001
From: Paul Kaplan <pkaplan@media.mit.edu>
Date: Tue, 5 Jun 2018 11:46:52 -0400
Subject: [PATCH] Fix bug with zero adding a costume/sound at index 0

---
 src/sprites/rendered-target.js | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/sprites/rendered-target.js b/src/sprites/rendered-target.js
index b6df05e6c..a21bfa4ab 100644
--- a/src/sprites/rendered-target.js
+++ b/src/sprites/rendered-target.js
@@ -488,10 +488,10 @@ class RenderedTarget extends Target {
      * @param {?int} index Index at which to add costume
      */
     addCostume (costumeObject, index) {
-        if (index) {
-            this.sprite.addCostumeAt(costumeObject, index);
-        } else {
+        if (typeof index === 'undefined') {
             this.sprite.addCostumeAt(costumeObject, this.sprite.costumes.length);
+        } else {
+            this.sprite.addCostumeAt(costumeObject, index);
         }
     }
 
@@ -551,10 +551,10 @@ class RenderedTarget extends Target {
     addSound (soundObject, index) {
         const usedNames = this.sprite.sounds.map(sound => sound.name);
         soundObject.name = StringUtil.unusedName(soundObject.name, usedNames);
-        if (index) {
-            this.sprite.sounds.splice(index, 0, soundObject);
-        } else {
+        if (typeof index === 'undefined') {
             this.sprite.sounds.push(soundObject);
+        } else {
+            this.sprite.sounds.splice(index, 0, soundObject);
         }
     }