make inter-component root and yield options _private

src/generators/dom/index.js

@@ -268,8 +268,8 @@ export default function dom ( parsed, source, options, names ) {
 
 	if ( templateProperties.onrender ) {
 		builders.init.addBlock( deindent`
-			if ( options.root ) {
-				options.root.__renderHooks.push({ fn: template.onrender, context: this });
+			if ( options._root ) {
+				options._root.__renderHooks.push({ fn: template.onrender, context: this });
 			} else {
 				template.onrender.call( this );
 			}
@@ -298,8 +298,8 @@ export default function dom ( parsed, source, options, names ) {
 			this.set = set;
 			this.teardown = teardown;
 
-			this.root = options.root;
-			this.yield = options.yield;
+			this._root = options._root;
+			this._yield = options._yield;
 
 			${builders.init}
 		}

src/generators/dom/visitors/Component.js

@@ -26,7 +26,7 @@ export default {
 
 		const componentInitProperties = [
 			`target: ${!isToplevel ? generator.current.target: 'null'}`,
-			'root: component.root || component'
+			'_root: component._root || component'
 		];
 
 		// Component has children, put them in a separate {{yield}} block
@@ -43,7 +43,7 @@ export default {
 				`${name}_yieldFragment.update( changed, root );`
 			);
 
-			componentInitProperties.push(`yield: ${name}_yieldFragment`);
+			componentInitProperties.push( `_yield: ${name}_yieldFragment`);
 		}
 
 		const statements = [];

src/generators/dom/visitors/YieldTag.js

@@ -4,11 +4,11 @@ export default {
 		generator.createAnchor( anchor, 'yield' );
 
 		generator.current.builders.mount.addLine(
-			`component.yield && component.yield.mount( ${generator.current.target}, ${anchor} );`
+			`component._yield && component._yield.mount( ${generator.current.target}, ${anchor} );`
 		);
 
 		generator.current.builders.teardown.addLine(
-			`component.yield && component.yield.teardown( detach );`
+			`component._yield && component._yield.teardown( detach );`
 		);
 	}
 };