addMapping(): ensure that originalLine and originalColumn are null when original argument was undefined/null. originalLine et all are checked using != null, which won't catch the potential false turning up due to the original code. (#395)

Author: GerHobbelt

lib/source-map-generator.js

@@ -124,8 +124,8 @@ class SourceMapGenerator {
     this._mappings.add({
       generatedLine: generated.line,
       generatedColumn: generated.column,
-      originalLine: original != null && original.line,
-      originalColumn: original != null && original.column,
+      originalLine: original && original.line,
+      originalColumn: original && original.column,
       source,
       name
     });