1 files changed, 21 insertions, 17 deletions
diff --git a/node_modules/merge-source-map/index.js b/node_modules/merge-source-map/index.js
index ef208d99c..2867fb7f5 100644
--- a/node_modules/merge-source-map/index.js
+++ b/node_modules/merge-source-map/index.js
@@ -13,11 +13,8 @@ module.exports = merge
  * @return {object|undefined} merged source map object, or undefined when both old and new source map are undefined
  */
 function merge(oldMap, newMap) {
-
-  if (!oldMap)
-    return newMap
-  if (!newMap)
-    return oldMap
+  if (!oldMap) return newMap
+  if (!newMap) return oldMap
 
   var oldMapConsumer = new SourceMapConsumer(oldMap)
   var newMapConsumer = new SourceMapConsumer(newMap)
@@ -25,15 +22,16 @@ function merge(oldMap, newMap) {
 
   // iterate on new map and overwrite original position of new map with one of old map
   newMapConsumer.eachMapping(function(m) {
-
     // pass when `originalLine` is null.
     // It occurs in case that the node does not have origin in original code.
-    if (m.originalLine == null)
-      return
+    if (m.originalLine == null) return
+
+    var origPosInOldMap = oldMapConsumer.originalPositionFor({
+      line: m.originalLine,
+      column: m.originalColumn
+    })
 
-    var origPosInOldMap = oldMapConsumer.originalPositionFor({line: m.originalLine, column: m.originalColumn})
-    if (origPosInOldMap.source == null)
-      return
+    if (origPosInOldMap.source == null) return
 
     mergedMapGenerator.addMapping({
       original: {
@@ -49,13 +47,19 @@ function merge(oldMap, newMap) {
     })
   })
 
-  var mergedMap = JSON.parse(mergedMapGenerator.toString())
-
-  mergedMap.sourcesContent = mergedMap.sources.map(function (source) {
-    return oldMapConsumer.sourceContentFor(source)
+  var consumers = [oldMapConsumer, newMapConsumer]
+  consumers.forEach(function(consumer) {
+    consumer.sources.forEach(function(sourceFile) {
+      mergedMapGenerator._sources.add(sourceFile)
+      var sourceContent = consumer.sourceContentFor(sourceFile)
+      if (sourceContent != null) {
+        mergedMapGenerator.setSourceContent(sourceFile, sourceContent)
+      }
+    })
   })
 
-  mergedMap.sourceRoot = oldMap.sourceRoot
+  mergedMapGenerator._sourceRoot = oldMap.sourceRoot
+  mergedMapGenerator._file = oldMap.file
 
-  return mergedMap
+  return JSON.parse(mergedMapGenerator.toString())
 }