Renderer track if element is root

lib/renderer.js

@@ -22,27 +22,37 @@ class PartialRenderer extends ReactDOMServerRenderer {
 
 		this._interrupts = [];
 
+		const isRootElement = stackState ? stackState.isRootElement : true;
+		this.isRootElement = isRootElement;
+
 		if (!stackState) return;
 
-		// Not root node.
-		// Add frame to stack to reinstate stack state from parent render
-		// and avoid `data-reactroot=""` markup on first element.
+		// Nested render
+		// Reinstate stack state from parent render.
+		// If not root element, add frame to stack to avoid `data-reactroot=""`
+		// markup on first element.
 		const {stack} = this;
 		const topFrame = stack[0];
 
-		const frame = {
-			type: null,
-			domNamespace: stackState.domNamespace,
-			children: topFrame.children,
-			childIndex: 0,
-			// Restore contexts from legacy Context API
-			context: stackState.context,
-			footer: ''
-		};
-		if (topFrame.debugElementStack) frame.debugElementStack = [];
-
-		stack[1] = frame;
-		topFrame.children = [];
+		if (isRootElement) {
+			// Add state to existing frame on stack
+			topFrame.domNamespace = stackState.domNamespace;
+			topFrame.context = stackState.context;
+		} else {
+			// Add frame to stack
+			const frame = {
+				type: null,
+				domNamespace: stackState.domNamespace,
+				children: topFrame.children,
+				childIndex: 0,
+				context: stackState.context,
+				footer: ''
+			};
+			if (topFrame.debugElementStack) frame.debugElementStack = [];
+
+			stack[1] = frame;
+			topFrame.children = [];
+		}
 
 		// Restore contexts from new Context API
 		const {threadID} = this;
@@ -81,7 +91,8 @@ class PartialRenderer extends ReactDOMServerRenderer {
 				// Capture contexts from legacy Context API
 				context,
 				contexts,
-				domNamespace
+				domNamespace,
+				isRootElement: this.isRootElement && this.stack.length === 1
 			}
 		};
 		if (props) Object.assign(interrupt, props);