small improvements

Author: Titanium2099

src/serialization/sb3.js

@@ -1542,7 +1542,7 @@ const replaceUnsafeCharsInVariableIds = function (targets) {
  * @returns {void|Promise<void>} Resolves when the user has acknowledged any compatibilities, if any exist.
  */
 const checkPlatformCompatibility = (json, runtime) => {
-    if (!json.meta || !json.meta.platform) {
+    if (!json.meta || !json.meta.platform || !runtime.platform) {
         return;
     }
 

src/util/math-util.js

@@ -64,6 +64,24 @@ class MathUtil {
         }
     }
 
+    /**
+     * Removes an element from the given array at the specified index and inserts it at a new index.
+     * @param {Array} array - The index of the element to remove.
+     * @param {number} fromIndex - The original index of the element to be swapped.
+     * @param {number} toIndex - The index to insert the removed element into.
+     */
+    static moveArrayElement (array, fromIndex, toIndex) {
+        fromIndex = MathUtil.clamp(fromIndex, 0, array.length - 1);
+        toIndex = MathUtil.clamp(toIndex, 0, array.length - 1);
+        if (fromIndex === toIndex) {
+            return {array, item: array[fromIndex], fromIndex, toIndex};
+        }
+        const newArr = [...array];
+        const deletedItem = newArr.splice(fromIndex, 1);
+        newArr.splice(toIndex, 0, deletedItem[0]);
+        return {array: newArr, item: deletedItem[0], fromIndex, toIndex};
+    }
+
     /**
      * Given an array of unique numbers,
      * returns a reduced array such that each element of the reduced array

test/integration/tw_very_long_comments.js

@@ -10,7 +10,7 @@ const path = require('path');
 test('serializes very long comments', t => {
     const rt = new Runtime();
     const sprite = new Sprite();
-    const target = new RenderedTarget(sprite);
+    const target = new RenderedTarget(sprite, rt);
     rt.addTarget(target);
 
     target.createComment('id_short', null, 'short comment', 0, 0, 20, 20, false);