From fec2c41580f9041fcc7d370e249b2bbecf6e5e43 Mon Sep 17 00:00:00 2001
From: Damir Murat <damir.murat.git@gmail.com>
Date: Fri, 31 Mar 2017 23:56:48 +0200
Subject: [PATCH] Use correct babel options for input source maps.

When there is no input source map, support generating a sourcemaps by letting a user to specify Babel sourceMaps option. It can be truthy value, 'inline' string or 'both' string, but it has to be specified by the user.
---
 index.js | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/index.js b/index.js
index 73b2806..5ab9f2f 100644
--- a/index.js
+++ b/index.js
@@ -26,19 +26,32 @@ module.exports = function (opts) {
 		}
 
 		try {
-			var fileOpts = objectAssign({}, opts, {
+			var isInputSourceMapPresent = Boolean(file.sourceMap);
+			var defaultOpts = {
 				filename: file.path,
-				filenameRelative: file.relative,
-				sourceMap: Boolean(file.sourceMap),
-				sourceFileName: file.relative,
-				sourceMapTarget: file.relative
-			});
+				filenameRelative: file.relative
+			};
+
+			if (isInputSourceMapPresent) {
+				defaultOpts.inputSourceMap = file.sourceMap;
+			}
+			else {
+				defaultOpts.sourceFileName = file.relative;
+				defaultOpts.sourceMapTarget = file.relative;
+			}
+
+			var fileOpts = objectAssign({}, opts, defaultOpts);
 
 			var res = babel.transform(file.contents.toString(), fileOpts);
 
 			if (file.sourceMap && res.map) {
-				res.map.file = replaceExtension(res.map.file);
-				applySourceMap(file, res.map);
+				if (isInputSourceMapPresent) {
+					file.sourceMap = res.map;
+				}
+				else {
+					res.map.file = replaceExtension(res.map.file);
+					applySourceMap(file, res.map);
+				}
 			}
 
 			if (!res.ignored) {