Record which keys the project has used

Related to TurboWarp/scratch-gui#1106

Author: GarboMuffin

src/io/keyboard.js

@@ -53,6 +53,10 @@ class Keyboard {
         // tw: track last pressed key
         this.lastKeyPressed = '';
         this._numeralKeyCodesToStringKey = new Map();
+        /**
+         * Set of Scratch keys used by the project.
+         */
+        this._usedKeys = new Set();
     }
 
     /**
@@ -198,13 +202,22 @@ class Keyboard {
             return this._keysPressed.length > 0;
         }
         const scratchKey = this._keyArgToScratchKey(keyArg);
+        this._usedKeys.add(scratchKey);
         return this._keysPressed.indexOf(scratchKey) > -1;
     }
 
     // tw: expose last pressed key
     getLastKeyPressed () {
         return this.lastKeyPressed;
     }
+
+    /**
+     * @param {string} scratchKey Scratch key
+     * @returns {boolean} true if the project has used this key
+     */
+    hasUsedKey (scratchKey) {
+        return this._usedKeys.has(scratchKey);
+    }
 }
 
 module.exports = Keyboard;

test/unit/io_keyboard_tw.js

@@ -110,3 +110,21 @@ test('holding shift and key, releasing shift, waiting, then releasing key', t =>
 
     t.end();
 });
+
+test('hasUsedKey', t => {
+    const rt = new Runtime();
+    const k = new Keyboard(rt);
+
+    t.equal(k.hasUsedKey('backspace'), false);
+    t.equal(k.hasUsedKey('delete'), false);
+
+    k.getKeyIsDown('backspace');
+    t.equal(k.hasUsedKey('backspace'), true);
+    t.equal(k.hasUsedKey('delete'), false);
+
+    k.getKeyIsDown('delete');
+    t.equal(k.hasUsedKey('backspace'), true);
+    t.equal(k.hasUsedKey('delete'), true);
+
+    t.end();
+});