Actions.SetXY has 2 new arguments: index and direction.

Author: photonstorm

src/actions/SetXY.js

@@ -4,32 +4,36 @@
  * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
  */
 
+var PropertyValueSet = require('./PropertyValueSet');
+
 /**
- * [description]
+ * Takes an array of Game Objects, or any objects that have the public properties `x` and `y`
+ * and then sets them to the given values.
+ * 
+ * The optional `stepX` and `stepY` properties are applied incrementally, multiplied by each item in the array.
+ * 
+ * To use this with a Group: `SetXY(group.getChildren(), x, y, stepX, stepY)`
  *
  * @function Phaser.Actions.SetXY
  * @since 3.0.0
  * 
- * @param {array} items - An array of Game Objects. The contents of this array are updated by this Action.
- * @param {number} x - [description]
- * @param {number} y - [description]
- * @param {number} [stepX=0] - [description]
- * @param {number} [stepY=0] - [description]
+ * @param {array|Phaser.GameObjects.GameObject[]} items - The array of items to be updated by this action.
+ * @param {number} x - The amount to set the `x` property to.
+ * @param {number} [y] - The amount to set the `y` property to. If `undefined` or `null` it uses the `x` value.
+ * @param {number} [stepX=0] - This is added to the `x` amount, multiplied by the iteration counter.
+ * @param {number} [stepY=0] - This is added to the `y` amount, multiplied by the iteration counter.
+ * @param {integer} [index=0] - An optional offset to start searching from within the items array.
+ * @param {integer} [direction=1] - The direction to iterate through the array. 1 is from beginning to end, -1 from end to beginning.
  *
- * @return {array} The array of Game Objects that was passed to this Action.
+ * @return {array} The array of objects that were passed to this Action.
  */
-var SetXY = function (items, x, y, stepX, stepY)
+var SetXY = function (items, x, y, stepX, stepY, index, direction)
 {
-    if (stepX === undefined) { stepX = 0; }
-    if (stepY === undefined) { stepY = 0; }
+    if (y === undefined || y === null) { y = x; }
 
-    for (var i = 0; i < items.length; i++)
-    {
-        items[i].x = x + (i * stepX);
-        items[i].y = y + (i * stepY);
-    }
+    PropertyValueSet(items, 'x', x, stepX, index, direction);
 
-    return items;
+    return PropertyValueSet(items, 'y', y, stepY, index, direction);
 };
 
 module.exports = SetXY;