diff --git a/swh/indexer/metadata_dictionary.py b/swh/indexer/metadata_dictionary.py
--- a/swh/indexer/metadata_dictionary.py
+++ b/swh/indexer/metadata_dictionary.py
@@ -161,15 +161,17 @@
     filename = b'package.json'
 
     _schema_shortcuts = {
-            'github': 'https://github.com/',
-            'gist': 'https://gist.github.com/',
-            'bitbucket': 'https://bitbucket.org/',
-            'gitlab': 'https://gitlab.com/',
+            'github': 'git+https://github.com/%s.git',
+            'gist': 'git+https://gist.github.com/%s.git',
+            'gitlab': 'git+https://gitlab.com/%s.git',
+            # Bitbucket supports both hg and git, and the shortcut does not
+            # tell which one to use.
+            # 'bitbucket': 'https://bitbucket.org/',
             }
 
     def normalize_repository(self, d):
         """https://docs.npmjs.com/files/package.json#repository"""
-        if isinstance(d, dict):
+        if isinstance(d, dict) and {'type', 'url'} <= set(d):
             url = '{type}+{url}'.format(**d)
         elif isinstance(d, str):
             if '://' in d:
@@ -177,11 +179,11 @@
             elif ':' in d:
                 (schema, rest) = d.split(':', 1)
                 if schema in self._schema_shortcuts:
-                    url = self._schema_shortcuts[schema] + rest
+                    url = self._schema_shortcuts[schema] % rest
                 else:
                     return None
             else:
-                url = self._schema_shortcuts['github'] + d
+                url = self._schema_shortcuts['github'] % d
 
         else:
             return None
@@ -189,7 +191,13 @@
         return {'@id': url}
 
     def normalize_bugs(self, d):
-        return {'@id': '{url}'.format(**d)}
+        """https://docs.npmjs.com/files/package.json#bugs"""
+        if isinstance(d, dict) and 'url' in d:
+            return {'@id': '{url}'.format(**d)}
+        elif isinstance(d, str):
+            return {'@id': d}
+        else:
+            return None
 
     _parse_author = re.compile(r'^ *'
                                r'(?P<name>.*?)'
diff --git a/swh/indexer/tests/test_metadata.py b/swh/indexer/tests/test_metadata.py
--- a/swh/indexer/tests/test_metadata.py
+++ b/swh/indexer/tests/test_metadata.py
@@ -248,6 +248,116 @@
         # The assertion below returns False sometimes because of nested lists
         self.assertEqual(expected_results, results)
 
+    def test_npm_bugs_normalization(self):
+        # valid dictionary
+        package_json = b"""{
+            "name": "foo",
+            "bugs": {
+                "url": "https://github.com/owner/project/issues",
+                "email": "foo@example.com"
+            }
+        }"""
+        result = MAPPINGS["NpmMapping"].translate(package_json)
+        self.assertEqual(result, {
+            '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+            'name': 'foo',
+            'issueTracker': 'https://github.com/owner/project/issues',
+            'type': 'SoftwareSourceCode',
+        })
+
+        # "invalid" dictionary
+        package_json = b"""{
+            "name": "foo",
+            "bugs": {
+                "email": "foo@example.com"
+            }
+        }"""
+        result = MAPPINGS["NpmMapping"].translate(package_json)
+        self.assertEqual(result, {
+            '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+            'name': 'foo',
+            'type': 'SoftwareSourceCode',
+        })
+
+        # string
+        package_json = b"""{
+            "name": "foo",
+            "bugs": "https://github.com/owner/project/issues"
+        }"""
+        result = MAPPINGS["NpmMapping"].translate(package_json)
+        self.assertEqual(result, {
+            '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+            'name': 'foo',
+            'issueTracker': 'https://github.com/owner/project/issues',
+            'type': 'SoftwareSourceCode',
+        })
+
+    def test_npm_repository_normalization(self):
+        # normal
+        package_json = b"""{
+            "name": "foo",
+            "repository": {
+                "type" : "git",
+                "url" : "https://github.com/npm/cli.git"
+            }
+        }"""
+        result = MAPPINGS["NpmMapping"].translate(package_json)
+        self.assertEqual(result, {
+            '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+            'name': 'foo',
+            'codeRepository': 'git+https://github.com/npm/cli.git',
+            'type': 'SoftwareSourceCode',
+        })
+
+        # missing url
+        package_json = b"""{
+            "name": "foo",
+            "repository": {
+                "type" : "git"
+            }
+        }"""
+        result = MAPPINGS["NpmMapping"].translate(package_json)
+        self.assertEqual(result, {
+            '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+            'name': 'foo',
+            'type': 'SoftwareSourceCode',
+        })
+
+        # github shortcut
+        package_json = b"""{
+            "name": "foo",
+            "repository": "github:npm/cli"
+        }"""
+        result = MAPPINGS["NpmMapping"].translate(package_json)
+        expected_result = {
+            '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+            'name': 'foo',
+            'codeRepository': 'git+https://github.com/npm/cli.git',
+            'type': 'SoftwareSourceCode',
+        }
+        self.assertEqual(result, expected_result)
+
+        # github shortshortcut
+        package_json = b"""{
+            "name": "foo",
+            "repository": "npm/cli"
+        }"""
+        result = MAPPINGS["NpmMapping"].translate(package_json)
+        self.assertEqual(result, expected_result)
+
+        # gitlab shortcut
+        package_json = b"""{
+            "name": "foo",
+            "repository": "gitlab:user/repo"
+        }"""
+        result = MAPPINGS["NpmMapping"].translate(package_json)
+        self.assertEqual(result, {
+            '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+            'name': 'foo',
+            'codeRepository': 'git+https://gitlab.com/user/repo.git',
+            'type': 'SoftwareSourceCode',
+        })
+
     def test_detect_metadata_package_json(self):
         # given
         df = [{