feat: ability to clear flyout blocks when language changes

src/engine/blocks.js

@@ -831,6 +831,14 @@ class Blocks {
         this.emitProjectChanged();
     }
 
+    /**
+     * Delete all blocks and their associated scripts.
+     */
+    deleteAllBlocks () {
+        const blockIds = Object.keys(this._blocks);
+        blockIds.forEach(blockId => this.deleteBlock(blockId));
+    }
+
     /**
      * Returns a map of all references to variables or lists from blocks
      * in this block container.

src/virtual-machine.js

@@ -1198,6 +1198,13 @@ class VirtualMachine extends EventEmitter {
         }
     }
 
+    /**
+     * Delete all of the flyout blocks.
+     */
+    clearFlyoutBlocks () {
+        this.runtime.flyoutBlocks.deleteAllBlocks();
+    }
+
     /**
      * Set an editing target. An editor UI can use this function to switch
      * between editing different targets, sprites, etc.

test/unit/virtual-machine.js

@@ -1055,3 +1055,16 @@ test('toJSON encodes Infinity/NaN as 0, not null', t => {
 
     t.end();
 });
+
+test('clearFlyoutBlocks removes all of the flyout blocks', t => {
+    const vm = new VirtualMachine();
+    const flyoutBlocks = vm.runtime.flyoutBlocks;
+
+    flyoutBlocks.createBlock(adapter(events.mockVariableBlock)[0]);
+    t.equal(Object.keys(flyoutBlocks._blocks).length, 1);
+
+    vm.clearFlyoutBlocks();
+    t.equal(Object.keys(flyoutBlocks._blocks).length, 0);
+
+    t.end();
+});