missing file addition :P

src/components/PreviewDimension.jsx

@@ -0,0 +1,38 @@
+import { h } from 'preact';
+import { PureComponent } from 'preact-compat';
+
+/**
+ * This component udpates not through props or state, but by some parent
+ * component calling a method of this component directly. This is because
+ * using the state/prop way causes a huge unnnecessary rendering as this
+ * component gets updated on drag event.
+ */
+const HIDE_AFTER_MILLISECONDS = 1000;
+export class PreviewDimension extends PureComponent {
+	constructor(props) {
+		super(props);
+		this.state = { w: 0, h: 0, isVisible: false };
+	}
+	update(dimensions) {
+		this.setState({ isVisible: true, ...dimensions });
+		if (this.hideTimer) {
+			clearTimeout(this.hideTimer);
+		}
+
+		/**
+		 * Automatically hide this commponent after sometime and also show
+		 * when its updated (code above).
+		 */
+		this.hideTimer = setTimeout(() => {
+			// this.setState({ isVisible: false });
+		}, HIDE_AFTER_MILLISECONDS);
+	}
+	render() {
+		if (!this.state.isVisible) return null;
+		return (
+			<div class="preview-dimension">
+				{this.state.w}px ⨯ {this.state.h}px
+			</div>
+		);
+	}
+}