add modifiedDate field to parser and frontmatter

src/frontmatter.js

@@ -39,6 +39,11 @@ export function id(post) {
 	return parseInt(post.id);
 }
 
+export function modifiedDate(post) {
+	// previously parsed as a raw string (e.g. "2013-12-09 06:24:33"), may be undefined
+	return post.modifiedDate;
+}
+
 export function slug(post) {
 	// previously parsed and decoded
 	return post.slug;

src/parser.js

@@ -98,6 +98,7 @@ function buildPost(data) {
 		isDraft: data.childValue('status') === 'draft',
 		slug: decodeURIComponent(data.childValue('post_name')),
 		date: getPostDate(data),
+		modifiedDate: data.optionalChildValue('post_modified'),
 		coverImageId: getPostMetaValue(data, '_thumbnail_id'),
 
 		// these are possibly set later in mergeImagesIntoPosts()

src/questions.js

@@ -110,7 +110,7 @@ export function load() {
 			name: 'frontmatter-fields',
 			type: 'list',
 			description: 'Frontmatter fields',
-			default: 'title,date,categories,tags,coverImage,draft'
+			default: 'title,date,modifiedDate,categories,tags,coverImage,draft'
 		},
 		{
 			name: 'request-delay',