1 files changed, 93 insertions, 0 deletions
diff --git a/pre_commit/languages/node.py b/pre_commit/languages/node.py
new file mode 100644
index 0000000..79ff807
--- /dev/null
+++ b/pre_commit/languages/node.py
@@ -0,0 +1,93 @@
+import contextlib
+import os
+import sys
+from typing import Generator
+from typing import Sequence
+from typing import Tuple
+
+import pre_commit.constants as C
+from pre_commit.envcontext import envcontext
+from pre_commit.envcontext import PatchesT
+from pre_commit.envcontext import Var
+from pre_commit.hook import Hook
+from pre_commit.languages import helpers
+from pre_commit.languages.python import bin_dir
+from pre_commit.prefix import Prefix
+from pre_commit.util import clean_path_on_failure
+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
+
+
+def _envdir(prefix: Prefix, version: str) -> str:
+    directory = helpers.environment_dir(ENVIRONMENT_DIR, version)
+    return prefix.path(directory)
+
+
+def get_env_patch(venv: str) -> PatchesT:
+    if sys.platform == 'cygwin':  # pragma: no cover
+        _, win_venv, _ = cmd_output('cygpath', '-w', venv)
+        install_prefix = fr'{win_venv.strip()}\bin'
+        lib_dir = 'lib'
+    elif sys.platform == 'win32':  # pragma: no cover
+        install_prefix = bin_dir(venv)
+        lib_dir = 'Scripts'
+    else:  # pragma: win32 no cover
+        install_prefix = venv
+        lib_dir = 'lib'
+    return (
+        ('NODE_VIRTUAL_ENV', venv),
+        ('NPM_CONFIG_PREFIX', install_prefix),
+        ('npm_config_prefix', install_prefix),
+        ('NODE_PATH', os.path.join(venv, lib_dir, 'node_modules')),
+        ('PATH', (bin_dir(venv), os.pathsep, Var('PATH'))),
+    )
+
+
+@contextlib.contextmanager
+def in_env(
+        prefix: Prefix,
+        language_version: str,
+) -> Generator[None, None, None]:
+    with envcontext(get_env_patch(_envdir(prefix, language_version))):
+        yield
+
+
+def install_environment(
+        prefix: Prefix, version: str, additional_dependencies: Sequence[str],
+) -> None:
+    additional_dependencies = tuple(additional_dependencies)
+    assert prefix.exists('package.json')
+    envdir = _envdir(prefix, version)
+
+    # https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx?f=255&MSPPError=-2147217396#maxpath
+    if sys.platform == 'win32':  # pragma: no cover
+        envdir = f'\\\\?\\{os.path.normpath(envdir)}'
+    with clean_path_on_failure(envdir):
+        cmd = [
+            sys.executable, '-mnodeenv', '--prebuilt', '--clean-src', envdir,
+        ]
+        if version != C.DEFAULT:
+            cmd.extend(['-n', version])
+        cmd_output_b(*cmd)
+
+        with in_env(prefix, version):
+            # https://npm.community/t/npm-install-g-git-vs-git-clone-cd-npm-install-g/5449
+            # install as if we installed from git
+            helpers.run_setup_cmd(prefix, ('npm', 'install'))
+            helpers.run_setup_cmd(
+                prefix,
+                ('npm', 'install', '-g', '.', *additional_dependencies),
+            )
+
+
+def run_hook(
+        hook: Hook,
+        file_args: Sequence[str],
+        color: bool,
+) -> Tuple[int, bytes]:
+    with in_env(hook.prefix, hook.language_version):
+        return helpers.run_xargs(hook, hook.cmd, file_args, color=color)