3 files changed, 21 insertions, 9 deletions
diff --git a/pre_commit/languages/docker.py b/pre_commit/languages/docker.py
index f449584..4091492 100644
--- a/pre_commit/languages/docker.py
+++ b/pre_commit/languages/docker.py
@@ -76,18 +76,18 @@ def install_environment(
         os.mkdir(directory)
 
 
-def get_docker_user() -> str:  # pragma: win32 no cover
+def get_docker_user() -> Tuple[str, ...]:  # pragma: win32 no cover
     try:
-        return f'{os.getuid()}:{os.getgid()}'
+        return ('-u', f'{os.getuid()}:{os.getgid()}')
     except AttributeError:
-        return '1000:1000'
+        return ()
 
 
 def docker_cmd() -> Tuple[str, ...]:  # pragma: win32 no cover
     return (
         'docker', 'run',
         '--rm',
-        '-u', get_docker_user(),
+        *get_docker_user(),
         # https://docs.docker.com/engine/reference/commandline/run/#mount-volumes-from-container-volumes-from
         # The `Z` option tells Docker to label the content with a private
         # unshared label. Only the current container can use a private volume.
diff --git a/pre_commit/languages/node.py b/pre_commit/languages/node.py
index 79ff807..9b636d3 100644
--- a/pre_commit/languages/node.py
+++ b/pre_commit/languages/node.py
@@ -1,4 +1,5 @@
 import contextlib
+import functools
 import os
 import sys
 from typing import Generator
@@ -6,6 +7,7 @@ from typing import Sequence
 from typing import Tuple
 
 import pre_commit.constants as C
+from pre_commit import parse_shebang
 from pre_commit.envcontext import envcontext
 from pre_commit.envcontext import PatchesT
 from pre_commit.envcontext import Var
@@ -18,10 +20,22 @@ from pre_commit.util import cmd_output
 from pre_commit.util import cmd_output_b
 
 ENVIRONMENT_DIR = 'node_env'
-get_default_version = helpers.basic_get_default_version
 healthy = helpers.basic_healthy
 
 
+@functools.lru_cache(maxsize=1)
+def get_default_version() -> str:
+    # nodeenv does not yet support `-n system` on windows
+    if sys.platform == 'win32':
+        return C.DEFAULT
+    # if node is already installed, we can save a bunch of setup time by
+    # using the installed version
+    elif all(parse_shebang.find_executable(exe) for exe in ('node', 'npm')):
+        return 'system'
+    else:
+        return C.DEFAULT
+
+
 def _envdir(prefix: Prefix, version: str) -> str:
     directory = helpers.environment_dir(ENVIRONMENT_DIR, version)
     return prefix.path(directory)
diff --git a/pre_commit/languages/python.py b/pre_commit/languages/python.py
index 5073a8b..85d8281 100644
--- a/pre_commit/languages/python.py
+++ b/pre_commit/languages/python.py
@@ -182,8 +182,8 @@ def py_interface(
             version: str,
             additional_dependencies: Sequence[str],
     ) -> None:
-        additional_dependencies = tuple(additional_dependencies)
         directory = helpers.environment_dir(_dir, version)
+        install = ('python', '-mpip', 'install', '.', *additional_dependencies)
 
         env_dir = prefix.path(directory)
         with clean_path_on_failure(env_dir):
@@ -193,9 +193,7 @@ def py_interface(
                 python = os.path.realpath(sys.executable)
             _make_venv(env_dir, python)
             with in_env(prefix, version):
-                helpers.run_setup_cmd(
-                    prefix, ('pip', 'install', '.') + additional_dependencies,
-                )
+                helpers.run_setup_cmd(prefix, install)
 
     return in_env, healthy, run_hook, install_environment