Merge pull request #292 from timbell/additional-empty-mappings-fix

handle empty mappings in applySourceMap

Author: tromey

lib/source-map-generator.js

@@ -197,7 +197,9 @@ SourceMapGenerator.prototype.applySourceMap =
     }
     // Applying the SourceMap can add and remove items from the sources and
     // the names array.
-    var newSources = new ArraySet();
+    var newSources = this._mappings.toArray().length > 0
+      ? new ArraySet()
+      : this._sources;
     var newNames = new ArraySet();
 
     // Find mappings for the "sourceFile"

test/test-source-map-generator.js

@@ -740,6 +740,18 @@ exports['test applySourceMap with unexact match'] = function (assert) {
   util.assertEqualMaps(assert, map1.toJSON(), expectedMap.toJSON());
 };
 
+exports['test applySourceMap with empty mappings'] = function (assert) {
+  var generator =  SourceMapGenerator.fromSourceMap(new SourceMapConsumer(util.testMapEmptyMappings));
+  generator.applySourceMap(new SourceMapConsumer(util.testMapEmptyMappings));
+  util.assertEqualMaps(assert, generator.toJSON(), util.testMapEmptyMappings);
+};
+
+exports['test applySourceMap with empty mappings and relative sources'] = function (assert) {
+  var generator =  SourceMapGenerator.fromSourceMap(new SourceMapConsumer(util.testMapEmptyMappingsRelativeSources));
+  generator.applySourceMap(new SourceMapConsumer(util.testMapEmptyMappingsRelativeSources));
+  util.assertEqualMaps(assert, generator.toJSON(), util.testMapEmptyMappingsRelativeSources_generatedExpected);
+};
+
 exports['test issue #192'] = function (assert) {
   var generator = new SourceMapGenerator();
   generator.addMapping({