added node hooks setup and jshint

pre_commit/languages/node.py

@@ -1,7 +1,40 @@
+import contextlib
+from plumbum import local
+from plumbum.machines.session import ShellSession
+from pre_commit.languages import helpers
+
+from pre_commit.languages import python
+
+NODE_ENV = 'node_env'
+
+@contextlib.contextmanager
+def in_env():
+    with ShellSession(local['bash'].popen()) as env:
+        env.run('. {0}/bin/activate'.format(NODE_ENV))
+        yield env
+
 
 def install_environment():
-    raise NotImplementedError
+    assert local.path('package.json').exists()
+
+    if local.path('node_env').exists():
+        return
+
+    # Install a virtualenv
+    local['virtualenv'][python.PY_ENV]()
+
+    with python.in_env() as python_env:
+        python_env.run('pip install nodeenv')
+
+        print "Creating nodeenv"
+        local['nodeenv'][NODE_ENV]()
+        print "Done nodeenv"
+
+        with in_env() as node_env:
+            node_env.run('npm install -g')
 
 
 def run_hook(hook, file_args):
-    raise NotImplementedError
+    with python.in_env():
+        with in_env() as node_env:
+            return helpers.run_hook(node_env, hook, file_args)