Make rendered targets in charge of deleting their own sounds and costumes

src/sprites/rendered-target.js

@@ -389,6 +389,39 @@ class RenderedTarget extends Target {
         this.runtime.requestTargetsUpdate(this);
     }
 
+    /**
+     * Delete a costume by index.
+     * @param {number} index Costume index to be deleted
+     */
+    deleteCostume (index) {
+        const originalCostumeCount = this.sprite.costumes.length;
+        if (originalCostumeCount === 1) return;
+
+        this.sprite.costumes = this.sprite.costumes
+            .slice(0, index)
+            .concat(this.sprite.costumes.slice(index + 1));
+
+        if (index === originalCostumeCount - 1) {
+            this.setCostume(index - 1);
+        } else {
+            this.setCostume(index);
+        }
+
+        this.runtime.requestTargetsUpdate(this);
+    }
+
+    /**
+     * Delete a sound by index.
+     * @param {number} index Sound index to be deleted
+     */
+    deleteSound (index) {
+        if (this.sprite.sounds.length === 1) return;
+        this.sprite.sounds = this.sprite.sounds
+            .slice(0, index)
+            .concat(this.sprite.sounds.slice(index + 1));
+        this.runtime.requestTargetsUpdate(this);
+    }
+
     /**
      * Update the rotation style.
      * @param {!string} rotationStyle New rotation style.

src/virtual-machine.js

@@ -291,13 +291,7 @@ class VirtualMachine extends EventEmitter {
      * @param {int} costumeIndex - the index of the costume to be removed.
      */
     deleteCostume (costumeIndex) {
-        this.editingTarget.sprite.costumes = this.editingTarget.sprite.costumes
-            .slice(0, costumeIndex)
-            .concat(this.editingTarget.sprite.costumes.slice(costumeIndex + 1));
-        if (costumeIndex === this.editingTarget.currentCostume) {
-            this.editingTarget.setCostume(costumeIndex - 1);
-        }
-        this.emitTargetsUpdate();
+        this.editingTarget.deleteCostume(costumeIndex);
     }
 
     /**
@@ -317,10 +311,7 @@ class VirtualMachine extends EventEmitter {
      * @param {int} soundIndex - the index of the sound to be removed.
      */
     deleteSound (soundIndex) {
-        this.editingTarget.sprite.sounds = this.editingTarget.sprite.sounds
-            .slice(0, soundIndex)
-            .concat(this.editingTarget.sprite.sounds.slice(soundIndex + 1));
-        this.emitTargetsUpdate();
+        this.editingTarget.deleteSound(soundIndex);
     }
 
     /**

test/unit/sprites_rendered-target.js

@@ -98,6 +98,71 @@ test('setCostume', t => {
     t.end();
 });
 
+test('deleteCostume', t => {
+    const o1 = {id: 1};
+    const o2 = {id: 2};
+    const o3 = {id: 3};
+
+    const s = new Sprite();
+    const r = new Runtime();
+    s.costumes = [o1, o2, o3];
+    const a = new RenderedTarget(s, r);
+    const renderer = new FakeRenderer();
+    a.renderer = renderer;
+
+    // Deleting costume keeps costume index at 0
+    a.setCostume(0);
+    a.deleteCostume(0);
+    t.deepEqual(a.sprite.costumes, [o2, o3]);
+    t.equals(a.currentCostume, 0);
+
+    // Deleting a costume in the middle maintains current costume index
+    a.sprite.costumes = [o1, o2, o3];
+    a.setCostume(1);
+    a.deleteCostume(1);
+    t.deepEqual(a.sprite.costumes, [o1, o3]);
+    t.equals(a.currentCostume, 1);
+
+    // Deleting last costume selects previous costume
+    a.sprite.costumes = [o1, o2, o3];
+    a.setCostume(2);
+    a.deleteCostume(2);
+    t.deepEqual(a.sprite.costumes, [o1, o2]);
+    t.equals(a.currentCostume, 1);
+
+    // Refuses to delete only costume
+    a.sprite.costumes = [o1];
+    a.setCostume(0);
+    a.deleteCostume(0);
+    t.deepEqual(a.sprite.costumes, [o1]);
+    t.equals(a.currentCostume, 0);
+
+    t.end();
+});
+
+test('deleteSound', t => {
+    const o1 = {id: 1};
+    const o2 = {id: 2};
+    const o3 = {id: 3};
+
+    const s = new Sprite();
+    const r = new Runtime();
+    s.sounds = [o1, o2, o3];
+    const a = new RenderedTarget(s, r);
+    const renderer = new FakeRenderer();
+    a.renderer = renderer;
+
+    a.deleteSound(0);
+    t.deepEqual(a.sprite.sounds, [o2, o3]);
+
+    // Refuses to delete only sound
+    a.sprite.sounds = [o1];
+    a.deleteSound(0);
+    t.deepEqual(a.sprite.sounds, [o1]);
+
+    t.end();
+});
+
 test('setRotationStyle', t => {
     const s = new Sprite();
     const r = new Runtime();