diff --git a/blocks/api/post.pegjs b/blocks/api/post.pegjs
index 85990a3bff61b..e53d9fa530524 100644
--- a/blocks/api/post.pegjs
+++ b/blocks/api/post.pegjs
@@ -1,3 +1,13 @@
+{
+
+function keyValue( key, value ) {
+  const o = {};
+  o[ key ] = value;
+  return o;
+}
+
+}
+
 Document
   = WP_Block_List
 
@@ -43,14 +53,7 @@ WP_Block_Type
 
 HTML_Attribute_List
   = as:(_+ a:HTML_Attribute_Item { return a })*
-  { return as.reduce( function( attrs, currentAttribute ) {
-			var currentAttrs = {};
-			currentAttrs[ currentAttribute[ 0 ] ] = currentAttribute[ 1 ];
-			return Object.assign(
-				attrs,
-				currentAttrs
-			);
-	}, {} ) }
+  { return as.reduce( function( attrs, attr ) { return Object.assign( attrs, attr ) }, {} ) }
 
 HTML_Attribute_Item
   = HTML_Attribute_Quoted
@@ -59,17 +62,17 @@ HTML_Attribute_Item
 
 HTML_Attribute_Empty
   = name:HTML_Attribute_Name
-  { return [ name, true ] }
+  { return keyValue( name, true ) }
 
 HTML_Attribute_Unquoted
   = name:HTML_Attribute_Name _* "=" _* value:$([a-zA-Z0-9]+)
-  { return [ name, value ] }
+  { return keyValue( name, value ) }
 
 HTML_Attribute_Quoted
-  = name:HTML_Attribute_Name _* "=" _* '"' value:$((!'"' .)*) '"'
-  { return [ name, value ] }
-  / name:HTML_Attribute_Name _* "=" _* "'" value:$((!"'" .)*) "'"
-  { return [ name, value ] }
+  = name:HTML_Attribute_Name _* "=" _* '"' value:$(('\\"' . / !'"' .)*) '"'
+  { return keyValue( name, value ) }
+  / name:HTML_Attribute_Name _* "=" _* "'" value:$(("\\'" . / !"'" .)*) "'"
+  { return keyValue( name, value ) }
 
 HTML_Attribute_Name
   = $([a-zA-Z0-9:.]+)
diff --git a/blocks/api/test/parser.js b/blocks/api/test/parser.js
index d5759318ccb26..506b33abdd429 100644
--- a/blocks/api/test/parser.js
+++ b/blocks/api/test/parser.js
@@ -156,7 +156,7 @@ describe( 'block parser', () => {
 					} );
 
 					const parsed = parse(
-						'<!-- wp:core/test-block smoked="yes" url="http://google.com" chicken="ribs & \'wings\'" checked -->' +
+						'<!-- wp:core/test-block smoked="yes" url="http://google.com" chicken="ribs & \'wings\'" -->' +
 						'Brisket' +
 						'<!-- /wp:core/test-block -->'
 					);
@@ -168,7 +168,6 @@ describe( 'block parser', () => {
 						smoked: 'yes',
 						url: 'http://google.com',
 						chicken: 'ribs & \'wings\'',
-						checked: true,
 					} );
 					expect( parsed[ 0 ].uid ).to.be.a( 'string' );
 				} );
diff --git a/post-content.js b/post-content.js
index 8b41b6d52f879..33b6cc98a1353 100644
--- a/post-content.js
+++ b/post-content.js
@@ -7,7 +7,7 @@ window._wpGutenbergPost = {
 	},
 	content: {
 		raw: [
-			'<!-- wp:core/text -->',
+			'<!-- wp:core/text data="{\\"projectName\\":\\"gutenberg\\",\\"isAwesome\\":true}"-->',
 			'<p>The goal of this new editor is to make adding rich content to WordPress simple and enjoyable. This whole post is composed of <em>pieces of content</em>—somewhat similar to LEGO bricks—that you can move around and interact with. Move your cursor around and you\'ll notice the different blocks light up with outlines and arrows. Press the arrows to reposition blocks quickly, without fearing about losing things in the process of copying and pasting.</p>',
 			'<p>What you are reading now is a <strong>text block</strong>, the most basic block of all. A text block can have multiple paragraphs, if that\'s how you prefer to write your posts. But you can also split it by hitting enter twice. Once blocks are split they get their own controls to be moved freely around the post...</p>',
 			'<!-- /wp:core/text -->',