Initial commit of 001code-html Scratch frontend project.

Includes scratch-gui, scratch-vm, scratch-blocks, scratch-render, scratch-l10n, and deployment config.

Co-authored-by: Cursor <cursoragent@cursor.com>

scratch-gui/src/lib/throttled-property-hoc.jsx

@@ -0,0 +1,49 @@
+import React from 'react';
+
+/* Higher Order Component to throttle updates to specific props.
+ * Why? Because certain prop updates are expensive, and need to be throttled.
+ * This allows renders when other properties change, and will use the last
+ * rendered value of a prop for comparison.
+ * @param {string} propName the name of the prop to throttle updates from.
+ * @param {string} throttleTime the minimum time between updates to that specific property.
+ * @returns {function} a function that accepts a component to wrap.
+ */
+const ThrottledPropertyHOC = function (propName, throttleTime) {
+    /**
+     * The function to be called with a React component to wrap it.
+     * @param {React.Component} WrappedComponent - Component to wrap with throttler.
+     * @returns {React.Component} the component wrapped with the throttler.
+     */
+    return function (WrappedComponent) {
+        class ThrottledPropertyWrapper extends React.Component {
+            shouldComponentUpdate (nextProps) {
+                for (const property in nextProps) {
+                    if (property !== propName && this.props[property] !== nextProps[property]) {
+                        return true; // Always update if another property has changed
+                    }
+                }
+
+                // If only that prop has changed, allow update to go to render based
+                // on _lastRenderedTime and _lastRenderTime are updated in render
+                if (nextProps[propName] !== this._lastRenderedValue &&
+                    Date.now() - this._lastRenderTime > throttleTime
+                ) {
+                    return true; // Allow this update to go to render
+                }
+
+                return false;
+            }
+            render () {
+                this._lastRenderTime = Date.now();
+                this._lastRenderedValue = this.props[propName];
+                return (
+                    <WrappedComponent {...this.props} />
+                );
+            }
+        }
+
+        return ThrottledPropertyWrapper;
+    };
+};
+
+export default ThrottledPropertyHOC;