diff --git a/lib/utils.js b/lib/utils.js
index 146a1c0..57ffbee 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -83,7 +83,7 @@ function getAlias(loader, canonicalName) {
       return;
 
     // get mapped without defaultJSExtension
-    var mapped = normalizePath(loader, loader.map[alias], true);
+    var mapped = getCanonicalName(loader, loader.normalizeSync(loader.map[alias]));
 
     // do matching with defaultJSExtension checking
     if (loader.defaultJSExtensions && canonicalName == mapped + '.js') {
diff --git a/test/utils.js b/test/utils.js
new file mode 100644
index 0000000..b7f8e10
--- /dev/null
+++ b/test/utils.js
@@ -0,0 +1,20 @@
+var Builder = require('../index');
+var builder = new Builder();
+
+builder.config({
+  paths: {
+    'npm:': 'node_modules/'
+  },
+  map: {
+    x: 'npm:x'
+  }
+});
+
+var utils = require('../lib/utils.js');
+
+suite('Aliasing', function() {
+  test('getAlias', function(done) {
+    assert.equal(utils.getAlias(builder.loader, 'npm:x'), 'x');
+    done();
+  });
+});
\ No newline at end of file