diff --git a/CHANGELOG.md b/CHANGELOG.md
index aa45f45..c7a1bbe 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 # Changelog
 
 * Reject in promise instead of throwing MISSING_DEST_DIR
+* In file transformers, use the destination filename extension to decide the sourcemap comment style. ([#116](https://github.com/gobblejs/gobble/issues/116))
 
 ## 0.11.3
 
diff --git a/src/builtins/map.js b/src/builtins/map.js
index 705867d..578f0b6 100644
--- a/src/builtins/map.js
+++ b/src/builtins/map.js
@@ -109,7 +109,7 @@ function processResult ( result, original, src, dest, codepath ) {
 		// if a sourcemap was returned, use it
 		if ( result.map ) {
 			return {
-				code: result.code.replace( SOURCEMAP_COMMENT, '' ) + getSourcemapComment( encodeURI( codepath + '.map' ), extname( codepath ) ),
+				code: result.code.replace( SOURCEMAP_COMMENT, '' ) + getSourcemapComment( encodeURI( codepath + '.map' ), extname( dest ) ),
 				map: processSourcemap( result.map, src, dest, original )
 			};
 		}