diff --git a/core/wisdom-maven-plugin/src/main/java/org/wisdom/maven/mojos/JavaScriptCompilerMojo.java b/core/wisdom-maven-plugin/src/main/java/org/wisdom/maven/mojos/JavaScriptCompilerMojo.java
index 7a7b4fea3..2d80a4c73 100644
--- a/core/wisdom-maven-plugin/src/main/java/org/wisdom/maven/mojos/JavaScriptCompilerMojo.java
+++ b/core/wisdom-maven-plugin/src/main/java/org/wisdom/maven/mojos/JavaScriptCompilerMojo.java
@@ -35,7 +35,9 @@
 
 import java.io.*;
 import java.nio.charset.Charset;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
 
 /**
  * Compiles and minifies JavaScript files.
@@ -215,11 +217,6 @@ private void compile(Aggregation aggregation) throws WatchingException {
             externs.add(new SourceFile(javascript.getExtern().getAbsolutePath()));
         }
 
-        if (googleClosureMap) {
-            options.setSourceMapFormat(SourceMap.Format.DEFAULT);
-            options.setSourceMapOutputPath(output.getPath());
-        }
-
         compiler.initOptions(options);
         final Result result = compiler.compile(externs, inputs, options);
         listErrors(result);
@@ -240,7 +237,7 @@ private void compile(Aggregation aggregation) throws WatchingException {
             }
         }
 
-        //Create the source map
+        //Create the source map file
         createSourceMapFile(output,compiler.getSourceMap());
     }
 
@@ -392,23 +389,13 @@ private void compile(File base) throws WatchingException {
         List<SourceFile> inputs = new ArrayList<>();
         List<SourceFile> externs = new ArrayList<>();
 
-        List<SourceMap.LocationMapping> mappingList = new ArrayList<>(files.size());
-
         for (File file : files) {
             if (file.isFile() && isNotMinified(file) && isNotInLibs(file)) {
                 store.add(file);
                 inputs.add(SourceFile.fromFile(file));
-                mappingList.add(new SourceMap.LocationMapping(getMinifiedFile(file).getParentFile().getPath(),
-                        getMinifiedFile(file).getParentFile().getPath()));
             }
         }
 
-        if (googleClosureMap) {
-            options.setSourceMapFormat(SourceMap.Format.DEFAULT);
-            options.setSourceMapOutputPath(buildDirectory.getPath());
-            options.setSourceMapLocationMappings(mappingList);
-        }
-
         compiler.initOptions(options);
         final Result result = compiler.compile(externs, inputs, options);
         listErrors(result);
@@ -454,6 +441,12 @@ protected CompilerOptions newCompilerOptions() {
         options.setWarningLevel(DiagnosticGroups.CHECK_VARIABLES,
                 CheckLevel.WARNING);
 
+        //Initialise source map options
+        if (googleClosureMap) {
+            options.setSourceMapFormat(SourceMap.Format.DEFAULT);
+            options.setSourceMapOutputPath(buildDirectory.getPath());
+        }
+
         return options;
     }
 
diff --git a/core/wisdom-maven-plugin/src/test/java/org/wisdom/maven/mojos/JavaScriptCompilerMojoTest.java b/core/wisdom-maven-plugin/src/test/java/org/wisdom/maven/mojos/JavaScriptCompilerMojoTest.java
index cf1c9a844..04de12802 100644
--- a/core/wisdom-maven-plugin/src/test/java/org/wisdom/maven/mojos/JavaScriptCompilerMojoTest.java
+++ b/core/wisdom-maven-plugin/src/test/java/org/wisdom/maven/mojos/JavaScriptCompilerMojoTest.java
@@ -31,8 +31,8 @@
 import java.io.IOException;
 
 import static java.util.Collections.singletonList;
+import static org.apache.commons.io.FileUtils.lineIterator;
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
@@ -119,7 +119,7 @@ public void testGetDefaultOutputFile() {
     }
 
     @Test
-    public void testAggregatedSourceMapFileIsCreated() {
+    public void testAggregatedSourceMapIsCreated() throws IOException, MojoExecutionException, MojoFailureException {
         JavaScriptCompilerMojo mojo = new JavaScriptCompilerMojo();
         mojo.googleClosureMinifierSuffix = "-min";
         mojo.basedir = new File("target/junk/root");
@@ -127,8 +127,8 @@ public void testAggregatedSourceMapFileIsCreated() {
         MavenProject project = mock(MavenProject.class);
         when(project.getArtifactId()).thenReturn("my-artifact");
         mojo.project = project;
-        mojo.googleClosureCompilationLevel= CompilationLevel.ADVANCED_OPTIMIZATIONS;
-        mojo.googleClosureMap=true;
+        mojo.googleClosureCompilationLevel = CompilationLevel.ADVANCED_OPTIMIZATIONS;
+        mojo.googleClosureMap = true;
 
         Aggregation aggregation = new Aggregation();
         aggregation.setMinification(true);
@@ -137,22 +137,34 @@ public void testAggregatedSourceMapFileIsCreated() {
         javascript.setAggregations(singletonList(new Aggregation()));
         mojo.javascript = javascript;
 
-        try {
-            mojo.execute();
-        } catch (MojoExecutionException | MojoFailureException e) {
-            fail("Cannot create the map file.",e);
-        }
+        mojo.execute();
 
-        File map = new File(mojo.getDefaultOutputFile(aggregation).getParentFile(),"my-artifact-min.js.map");
+        File map = new File(mojo.getDefaultOutputFile(aggregation).getParentFile(), "my-artifact-min.js.map");
 
         assertThat(mojo.getDefaultOutputFile(aggregation)).hasContent("\n//# sourceMappingURL=my-artifact-min.js.map");
         assertThat(map).exists();
-
-        try {
-            assertThat(FileUtils.lineIterator(map)).contains("\"file\":\"my-artifact-min.js\",");
-        } catch (IOException e) {
-            fail("Cannot read map file",e);
-        }
+        assertThat(lineIterator(map)).contains("\"file\":\"my-artifact-min.js\",");
     }
 
+    @Test
+    public void testSourceMapIsCreatedForInternal() throws IOException, MojoExecutionException, MojoFailureException {
+        JavaScriptCompilerMojo mojo = new JavaScriptCompilerMojo();
+        mojo.googleClosureMinifierSuffix = "-min";
+        mojo.basedir = new File("target/test-classes/fake-project");
+        mojo.buildDirectory = new File(mojo.basedir, "target");
+        mojo.getInternalAssetOutputDirectory().mkdirs();
+        mojo.googleClosureMap = true;
+
+        FileUtils.copyFileToDirectory(new File(mojo.getExternalAssetsDirectory(), "street.js"),
+                mojo.getInternalAssetOutputDirectory());
+        mojo.googleClosureCompilationLevel = CompilationLevel.ADVANCED_OPTIMIZATIONS;
+
+        mojo.execute();
+
+        File min = new File(mojo.getInternalAssetOutputDirectory(), "street-min.js");
+        File map = new File(mojo.getInternalAssetOutputDirectory(), "street-min.js.map");
+
+        assertThat(lineIterator(min)).endsWith("//# sourceMappingURL=street-min.js.map");
+        assertThat(map).exists();
+    }
 }
diff --git a/core/wisdom-maven-plugin/src/test/resources/fake-project/src/main/assets/street.js b/core/wisdom-maven-plugin/src/test/resources/fake-project/src/main/assets/street.js
new file mode 100644
index 000000000..8bc276e5c
--- /dev/null
+++ b/core/wisdom-maven-plugin/src/test/resources/fake-project/src/main/assets/street.js
@@ -0,0 +1,2 @@
+var msg = "Here comes a new challenger";
+console.log(msg);
\ No newline at end of file