Add methods for moving layers

src/style_manager/model/Layer.js

@@ -93,6 +93,14 @@ export default class Layer extends Model {
     return this.prop?.removeLayer(this);
   }
 
+  /**
+   * Move layer to a new index.
+   * @param {Number} index New index
+   */
+  move(index) {
+    return this.prop?.moveLayer(this, index);
+  }
+
   upValues(props = {}) {
     return this.set('values', {
       ...this.getValues(),

src/style_manager/model/PropertyStack.js

@@ -1,4 +1,4 @@
-import { keys, isUndefined, isArray, isString } from 'underscore';
+import { keys, isUndefined, isArray, isString, isNumber } from 'underscore';
 import PropertyComposite, { isNumberType } from './PropertyComposite';
 import PropertyBase from './Property';
 import Layers from './Layers';
@@ -111,6 +111,23 @@ export default class PropertyStack extends PropertyComposite {
     return layer && this.selectLayer(layer);
   }
 
+  /**
+   * Move layer by index.
+   * @param {[Layer]} layer Layer to move.
+   * @param {Number} index New layer index.
+   * @example
+   * const layer = property.getLayer(1);
+   * property.moveLayer(layer, 0);
+   */
+  moveLayer(layer, index = 0) {
+    const currIndex = layer ? layer.getIndex() : -1;
+
+    if (currIndex >= 0 && isNumber(index) && index >= 0 && index < this.getLayers().length && currIndex !== index) {
+      this.removeLayer(layer);
+      this.__getLayers().add(layer, { at: index });
+    }
+  }
+
   /**
    * Add new layer to the stack.
    * @param {Object} [props={}] Custom property values to use in a new layer.