Example/debug frontmatter getter

src/frontmatter/debug.js

@@ -0,0 +1,19 @@
+/*
+  1. Copy this file, rename to the frontmatter field name you want, camelcased
+  2. Edit frontmatter_fields in settings.js to include your new field name
+  3. Run the script to see post data dumps, to see what you can work with
+  4. Write your code to get and return what you want
+  5. Update "get whatever" comment to describe what you're getting
+  6. Remove your field name from the default frontmatter_fields in settings.js
+  7. Remove this comment block and the console debug code
+  8. Make that pull request!
+*/
+
+// get whatever
+module.exports = (post) => {
+  console.log('\nBEGIN POST DATA DUMP ===========================================================\n');
+  console.dir(post, { depth: null });
+  console.log('\nEND POST DATA DUMP =============================================================\n');
+
+  return 'DEBUG: ' + post.data.title[0];
+};

src/parser.js

@@ -171,7 +171,7 @@ function mergeImagesIntoPosts(images, posts) {
 
 function populateFrontmatter(posts) {
 	posts.forEach(post => {
-		post.frontmatter = {};
+		const frontmatter = {};
 		settings.frontmatter_fields.forEach(field => {
 			[key, alias] = field.split(':');
 
@@ -180,8 +180,9 @@ function populateFrontmatter(posts) {
 				throw `Could not find a frontmatter getter named "${key}".`;
 			}
 
-			post.frontmatter[alias || key] = frontmatterGetter(post);
+			frontmatter[alias || key] = frontmatterGetter(post);
 		});
+		post.frontmatter = frontmatter;
 	});
 }