Add --version

.gitignore

@@ -3,3 +3,4 @@
 *.lock
 __pycache__/
 dist/
+/_version.py

fastapi_vue_setup.py

@@ -13,21 +13,22 @@ Options:
 import argparse
 import os
 import re
-import shutil
 import subprocess
 import sys
+import tomllib
 from pathlib import Path
 from textwrap import indent
 
-import tomlkit
+import tomli_w
+
+try:
+    from _version import __version__
+except ImportError:
+    __version__ = "0.0.0+unknown"
 
 # Template directory
 TEMPLATE_DIR = Path(__file__).parent / "template"
 
-# Marker comment indicating file can be auto-upgraded
-# Users should remove this line to prevent automatic updates
-UPGRADE_MARKER = "auto-upgrade@fastapi-vue-setup"
-
 # pyproject.toml additions for patched projects
 PYPROJECT_ADDITIONS = {
     "tool": {
@@ -52,7 +53,9 @@ PYPROJECT_ADDITIONS = {
 # Frontend instantiation block for patching existing apps
 FRONTEND_BLOCK = """
 # Vue Frontend static files
-frontend = Frontend(Path(__file__).with_name("frontend-build"), cached=["/assets/"])
+frontend = Frontend(
+    Path(__file__).with_name("frontend-build"), spa=True, cached=["/assets/"]
+)
 """
 
 # TypeScript health check script for Vue components
@@ -128,7 +131,8 @@ def find_module_name(project_dir: Path) -> str | None:
     if not pyproject.exists():
         return None
 
-    data = tomlkit.parse(pyproject.read_text())
+    with open(pyproject, "rb") as f:
+        data = tomllib.load(f)
 
     if "project" in data and "name" in data["project"]:
         name = data["project"]["name"]
@@ -137,18 +141,10 @@ def find_module_name(project_dir: Path) -> str | None:
     return None
 
 
-def find_fastapi_app(
+def find_fastapi_app(module_dir: Path) -> tuple[Path, str] | None:
-    module_dir: Path, project_dir: Path | None = None
-) -> tuple[Path, str] | None:
     """Find the FastAPI app in a module directory.
 
     Returns (file_path, app_variable_name) or None if not found.
-
-    Search order:
-    1. Common app files in module_dir (app.py, main.py, etc.)
-    2. All .py files in module_dir
-    3. Subpackage indicated by CLI entrypoint in pyproject.toml
-    4. Follow re-exports in __init__.py files
     """
     # Common app file names to check first
     candidates = ["app.py", "main.py", "server.py", "api.py", "__init__.py"]
@@ -161,155 +157,13 @@ def find_fastapi_app(
             if result:
                 return path, result
 
-    # Then check all .py files in module_dir
+    # Then check all .py files
     for path in module_dir.glob("*.py"):
         if path.name not in candidates:
             result = _find_app_in_file(path)
             if result:
                 return path, result
 
-    # Try to find app via CLI entrypoint in pyproject.toml
-    if project_dir:
-        result = _find_app_via_entrypoint(module_dir, project_dir)
-        if result:
-            return result
-
-    return None
-
-
-def _find_app_via_entrypoint(
-    module_dir: Path, project_dir: Path
-) -> tuple[Path, str] | None:
-    """Find FastAPI app by following the CLI entrypoint in pyproject.toml.
-
-    If pyproject.toml has a script like `myapp = "myapp.subpkg.__main__:main"`,
-    look in myapp/subpkg/ for the app (checking __init__.py exports and common files).
-    """
-    pyproject = project_dir / "pyproject.toml"
-    if not pyproject.exists():
-        return None
-
-    try:
-        data = tomlkit.parse(pyproject.read_text())
-    except Exception:
-        return None
-
-    scripts = data.get("project", {}).get("scripts", {})
-    if not scripts:
-        return None
-
-    module_name = module_dir.name
-
-    # Find script entries that reference this module
-    for script_name, entry in scripts.items():
-        if not isinstance(entry, str):
-            continue
-        # Parse entry like "module.subpkg.__main__:main"
-        if ":" not in entry:
-            continue
-        module_path, _ = entry.rsplit(":", 1)
-        parts = module_path.split(".")
-
-        # Check if this entry starts with our module
-        if not parts or parts[0] != module_name:
-            continue
-
-        # If there's a subpackage (e.g., module.fastapi.__main__), check there
-        if len(parts) >= 2:
-            # Build path to subpackage (exclude __main__ or similar)
-            subpkg_parts = [p for p in parts[1:] if not p.startswith("_")]
-            if subpkg_parts:
-                subpkg_dir = module_dir / "/".join(subpkg_parts)
-                if subpkg_dir.is_dir():
-                    result = _find_app_in_subpackage(subpkg_dir)
-                    if result:
-                        return result
-
-    return None
-
-
-def _find_app_in_subpackage(subpkg_dir: Path) -> tuple[Path, str] | None:
-    """Find FastAPI app in a subpackage, following __init__.py exports."""
-    # First check __init__.py for re-exports like `from .mainapp import app`
-    init_file = subpkg_dir / "__init__.py"
-    if init_file.exists():
-        result = _follow_init_reexport(init_file, subpkg_dir)
-        if result:
-            return result
-
-    # Check common app file names in subpackage
-    for name in ["app.py", "main.py", "mainapp.py", "server.py", "api.py"]:
-        path = subpkg_dir / name
-        if path.exists():
-            result = _find_app_in_file(path)
-            if result:
-                return path, result
-
-    return None
-
-
-def _find_existing_cli_entrypoint(project_dir: Path, module_name: str) -> str | None:
-    """Check if pyproject.toml already has a CLI entrypoint for this module.
-
-    Returns the entrypoint string if found, None otherwise.
-    """
-    pyproject = project_dir / "pyproject.toml"
-    if not pyproject.exists():
-        return None
-
-    try:
-        data = tomlkit.parse(pyproject.read_text())
-    except Exception:
-        return None
-
-    scripts = data.get("project", {}).get("scripts", {})
-    if not scripts:
-        return None
-
-    # Look for any script that references our module
-    for script_name, entry in scripts.items():
-        if isinstance(entry, str) and entry.startswith(f"{module_name}."):
-            return f'{script_name} = "{entry}"'
-
-    return None
-
-
-def _follow_init_reexport(init_file: Path, subpkg_dir: Path) -> tuple[Path, str] | None:
-    """Follow a re-export in __init__.py to find the actual app file.
-
-    Looks for patterns like:
-    - from .mainapp import app
-    - from module.subpkg.mainapp import app
-    """
-    try:
-        content = init_file.read_text()
-    except Exception:
-        return None
-
-    # Look for: from .module import app (or similar variable names)
-    # Pattern matches: from .mainapp import app, application, etc.
-    pattern = r"from\s+\.(\w+)\s+import\s+(\w+)"
-    for match in re.finditer(pattern, content):
-        module_name, var_name = match.groups()
-        if var_name.lower() in ("app", "application", "api"):
-            target_file = subpkg_dir / f"{module_name}.py"
-            if target_file.exists():
-                # Verify the app is actually there
-                app_var = _find_app_in_file(target_file)
-                if app_var:
-                    return target_file, app_var
-
-    # Also check for absolute imports: from pkg.subpkg.module import app
-    abs_pattern = r"from\s+[\w.]+\.(\w+)\s+import\s+(\w+)"
-    for match in re.finditer(abs_pattern, content):
-        module_name, var_name = match.groups()
-        if var_name.lower() in ("app", "application", "api"):
-            target_file = subpkg_dir / f"{module_name}.py"
-            if target_file.exists():
-                app_var = _find_app_in_file(target_file)
-                if app_var:
-                    return target_file, app_var
-
     return None
 
 
@@ -351,15 +205,19 @@ def patch_app_file(
         print(f"❌ Cannot patch {path} - file not found")
         return False
 
-    original_content = path.read_text()
+    content = path.read_text()
     marker = "from fastapi_vue import Frontend"
 
-    if marker in original_content:
+    if marker in content:
-        print(f"✔️  {path} (already patched)")
+        print(f"⚠️  Skipping {path} (already patched)")
         return False
 
+    if dry_run:
+        print(f"[DRY RUN] Would patch {path}")
+        return True
+
     # Find where to insert the import (after other imports)
-    lines = original_content.split("\n")
+    lines = content.split("\n")
     import_line = "from fastapi_vue import Frontend"
 
     route_line = f'frontend.route({app_var}, "/")'
@@ -377,11 +235,6 @@ def patch_app_file(
             # Stop at first non-import, non-comment, non-empty line after imports
             break
 
-    # Check if we found imports to insert after
-    if last_import_idx == 0 and not lines[0].strip().startswith(("import ", "from ")):
-        print(f"⚠️  Skipping {path} (no imports found to patch)")
-        return False
-
     # Insert imports after last import, then frontend instantiation
     if not has_pathlib:
         lines.insert(last_import_idx + 1, "from pathlib import Path")
@@ -391,33 +244,35 @@ def patch_app_file(
 
     # Append route at end
     lines.append("")
-    lines.append("# Serve the Vue frontend (needs to be last if SPA catch-all is used)")
     lines.append(route_line)
     content = "\n".join(lines)
 
-    # Try to patch lifespan function - insert await frontend.load() before yield
+    # Try to patch lifespan function
     lifespan_patched = False
 
-    # Look for yield inside an async def lifespan function
+    # Look for async def lifespan pattern and insert after the opening (and docstring if present)
-    # Find the yield statement and insert before it
+    lifespan_pattern = r"(async\s+def\s+lifespan\s*\([^)]*\)\s*(?:->.*?)?:\s*\n)"
-    yield_pattern = r"^([ \t]+)(yield\b)"
+    match = re.search(lifespan_pattern, content)
-    yield_match = re.search(yield_pattern, content, re.MULTILINE)
+    if match:
-    if yield_match:
+        insert_pos = match.end()
-        indent = yield_match.group(1)
+        rest = content[insert_pos:]
-        insert_pos = yield_match.start()
+
+        # Detect indentation from the next line
+        indent_match = re.match(r"([ \t]*)", rest)
+        indent = (
+            indent_match.group(1) if indent_match and indent_match.group(1) else "    "
+        )
+
+        # Check if there's a docstring and skip past it
+        docstring_pattern = r'^([ \t]*)("""[\s\S]*?"""|\'\'\'\'[\s\S]*?\'\'\')\s*\n'
+        docstring_match = re.match(docstring_pattern, rest)
+        if docstring_match:
+            insert_pos += docstring_match.end()
+
         load_code = f"{indent}await frontend.load()\n"
         content = content[:insert_pos] + load_code + content[insert_pos:]
         lifespan_patched = True
 
-    # Check if content actually changed
-    if content == original_content:
-        print(f"⚠️  Skipping {path} (no changes needed)")
-        return False
-
-    if dry_run:
-        print(f"[DRY RUN] Would patch {path}")
-        return True
-
     path.write_text(content)
     print(f"✅ Patched {path}")
 
@@ -453,17 +308,21 @@ def patch_vite_config(
         print(f"❌ Cannot patch {path} - file not found")
         return False
 
-    original_content = path.read_text()
+    content = path.read_text()
     marker = "vite-plugin-fastapi"
 
-    if marker in original_content:
+    if marker in content:
-        print(f"✔️  {path} (already patched)")
+        print(f"⚠️  Skipping {path} (already patched)")
         return False
 
+    if dry_run:
+        print(f"[DRY RUN] Would patch {path}")
+        return True
+
     # Add import for the plugin at the top (after other imports)
     import_line = f"import fastapiVue from './{marker}.js'"
 
-    lines = original_content.split("\n")
+    lines = content.split("\n")
     new_lines = []
     import_inserted = False
 
@@ -495,18 +354,6 @@ def patch_vite_config(
     if match:
         insert_pos = match.end()
         content = content[:insert_pos] + "\n    fastapiVue()," + content[insert_pos:]
-    else:
-        print(f"⚠️  Skipping {path} (no plugins array found)")
-        return False
-
-    # Check if content actually changed
-    if content == original_content:
-        print(f"⚠️  Skipping {path} (no changes needed)")
-        return False
-
-    if dry_run:
-        print(f"[DRY RUN] Would patch {path}")
-        return True
 
     path.write_text(content)
     print(f"✅ Patched {path}")
@@ -542,14 +389,16 @@ def patch_frontend_health_check(frontend_dir: Path, dry_run: bool = False) -> bo
         print("⚠️  No Vue file found to patch, skipping frontend health check")
         return False
 
-    original_content = target_file.read_text()
+    content = target_file.read_text()
 
     # Check if already patched
-    if "/api/health" in original_content:
+    if "/api/health" in content:
-        print(f"✔️  {target_file} (already patched)")
+        print(f"⚠️  Skipping {target_file} (already patched)")
         return False
 
-    content = original_content
+    if dry_run:
+        print(f"[DRY RUN] Would patch {target_file}")
+        return True
 
     # Detect if TypeScript (has lang="ts" in script tag)
     is_typescript = 'lang="ts"' in content
@@ -561,98 +410,47 @@ def patch_frontend_health_check(frontend_dir: Path, dry_run: bool = False) -> bo
 
     # Insert script addition before </script>
     script_end_match = re.search(r"</script>", content)
-    if not script_end_match:
+    if script_end_match:
-        print(f"⚠️  Skipping {target_file} (no </script> tag found)")
-        return False
-
         insert_pos = script_end_match.start()
         content = content[:insert_pos] + script_addition + content[insert_pos:]
 
     # Insert status inline - find the best place based on file type
     # For HelloWorld.vue: insert before </h3>
-    # For App.vue (minimal): only patch if it's the default "You did it!" template
+    # For App.vue (minimal): insert before the last </p> in template
     if "HelloWorld" in str(target_file):
         # Insert before closing </h3>
         h3_close = content.find("    </h3>")
         if h3_close == -1:
-            print(
-                f"⚠️  Skipping {target_file} (no </h3> tag found for status insertion)"
-            )
             return False
         before, after = content[:h3_close], content[h3_close:]
         content = f"{before}{indent(STATUS_SPAN_TEMPLATE, '  ')}{after}"
     else:
-        # Minimal App.vue - only patch if it contains the default welcome message
+        # Minimal App.vue - insert before the last </p> before </template>
-        if "<h1>You did it!</h1>" not in content:
-            print(f"⚠️  Skipping {target_file} (not a default Vue template)")
-            return False
-        # Insert before the </p> tag
         template_end = content.find("</template>")
-        if template_end == -1:
+        if template_end != -1:
-            print(f"⚠️  Skipping {target_file} (no </template> tag found)")
+            # Find last </p> before </template>
-            return False
-        # Find </p> before </template>
             last_p = content.rfind("  </p>", 0, template_end)
             if last_p == -1:
-            print(f"⚠️  Skipping {target_file} (no </p> tag found for status insertion)")
                 return False
             before, after = content[:last_p], content[last_p:]
             content = f"{before}{STATUS_SPAN_TEMPLATE}{after}"
 
-    # Check if content actually changed
-    if content == original_content:
-        print(f"⚠️  Skipping {target_file} (no changes needed)")
-        return False
-
-    if dry_run:
-        print(f"[DRY RUN] Would patch {target_file}")
-        return True
-
     target_file.write_text(content)
     print(f"✅ Patched {target_file}")
     return True
 
 
-# Track .new.py files written during setup (for merge notification)
-_new_files_written: list[tuple[Path, Path]] = []
-
-
 def write_file(
     path: Path,
     content: str,
     overwrite: bool = True,
     dry_run: bool = False,
     executable: bool = False,
-    fallback_path: Path | None = None,
-    force: bool = False,
 ) -> bool:
-    """Write content to a file, handling existing files and dry-run.
+    """Write content to a file, handling existing files and dry-run."""
-
-    If fallback_path is provided and the file exists without the upgrade marker,
-    the content will be written to fallback_path instead of being skipped.
-
-    If force=True, always overwrite without checking for upgrade marker.
-    """
     exists = path.exists()
     if exists and not overwrite:
-        print(f"ℹ️  Skipping {path} (exists)")
+        print(f"⚠️  Skipping {path} (exists)")
-        return False
-
-    # Check if content is the same
-    if exists:
-        existing_content = path.read_text()
-        if existing_content == content:
-            print(f"✔️  {path} (already up to date)")
-            return False
-
-        # If overwrite requested but file doesn't have upgrade marker (unless force)
-        if overwrite and not force and UPGRADE_MARKER not in existing_content:
-            if fallback_path is not None:
-                # Write to fallback path instead
-                return _write_fallback_file(
-                    path, fallback_path, content, dry_run, executable
-                )
-            print(f"ℹ️  Skipping {path} (customized by user)")
         return False
 
     if dry_run:
@@ -669,114 +467,47 @@ def write_file(
     return True
 
 
-def _write_fallback_file(
+def merge_pyproject(data: dict, additions: dict, module_name: str) -> dict:
-    original_path: Path,
+    """Merge additions into pyproject.toml data."""
-    fallback_path: Path,
+    result = data.copy()
-    content: str,
-    dry_run: bool,
-    executable: bool,
-) -> bool:
-    """Write content to a fallback .new.py file when original can't be overwritten."""
-    # Check if fallback already has same content
-    if fallback_path.exists():
-        if fallback_path.read_text() == content:
-            print(f"✔️  {fallback_path} (already up to date)")
-            return False
 
-    if dry_run:
-        print(f"[DRY RUN] Would create {fallback_path} (original customized by user)")
-        _new_files_written.append((fallback_path, original_path))
-        return True
-
-    fallback_path.parent.mkdir(parents=True, exist_ok=True)
-    fallback_path.write_text(content)
-    if executable and sys.platform != "win32":
-        fallback_path.chmod(fallback_path.stat().st_mode | 0o111)
-    print(f"✅ Created {fallback_path} (original customized by user)")
-    _new_files_written.append((fallback_path, original_path))
-    return True
-
-
-def merge_pyproject(
-    data: tomlkit.TOMLDocument, additions: dict, module_name: str
-) -> tomlkit.TOMLDocument:
-    """Merge additions into pyproject.toml data, preserving comments and existing values."""
     # Ensure hatchling build system is configured
-    if "build-system" not in data:
+    if "build-system" not in result:
-        data["build-system"] = tomlkit.table()
+        result["build-system"] = {}
+    result["build-system"]["requires"] = ["hatchling"]
+    result["build-system"]["build-backend"] = "hatchling.build"
 
-    # Add hatchling to requires if not present, preserving existing requires
+    # Add dependencies
-    if "requires" not in data["build-system"]:
+    if "project" not in result:
-        data["build-system"]["requires"] = ["hatchling"]
+        result["project"] = {}
-    else:
+    if "dependencies" not in result["project"]:
-        requires = list(data["build-system"]["requires"])
+        result["project"]["dependencies"] = []
-        if not any(r.startswith("hatchling") for r in requires):
-            requires.insert(0, "hatchling")
-            data["build-system"]["requires"] = requires
-
-    if "build-backend" not in data["build-system"]:
-        data["build-system"]["build-backend"] = "hatchling.build"
-
-    # Ensure project table exists
-    if "project" not in data:
-        data["project"] = tomlkit.table()
-
-    # Ensure Python version is at least 3.11 (required by fastapi-vue)
-    if "requires-python" in data["project"]:
-        req = data["project"]["requires-python"]
-        # Parse minimum version from strings like ">=3.10" or ">=3.9,<4"
-        import re
-
-        match = re.search(r">=\s*(\d+)\.(\d+)", req)
-        if match:
-            major, minor = int(match.group(1)), int(match.group(2))
-            if major < 3 or (major == 3 and minor < 11):
-                data["project"]["requires-python"] = ">=3.11"
-    else:
-        data["project"]["requires-python"] = ">=3.11"
 
     # Add hatch build config
-    if "tool" not in data:
+    if "tool" not in result:
-        data["tool"] = tomlkit.table()
+        result["tool"] = {}
-    if "hatch" not in data["tool"]:
+    if "hatch" not in result["tool"]:
-        data["tool"]["hatch"] = tomlkit.table()
+        result["tool"]["hatch"] = {}
-    if "build" not in data["tool"]["hatch"]:
+    if "build" not in result["tool"]["hatch"]:
-        data["tool"]["hatch"]["build"] = tomlkit.table()
+        result["tool"]["hatch"]["build"] = {}
 
-    hatch_build = data["tool"]["hatch"]["build"]
+    hatch_build = additions["tool"]["hatch"]["build"]
-    hatch_additions = additions["tool"]["hatch"]["build"]
+    result["tool"]["hatch"]["build"]["packages"] = [
+        p.replace("MODULE_NAME", module_name) for p in hatch_build["packages"]
+    ]
+    result["tool"]["hatch"]["build"]["artifacts"] = [
+        a.replace("MODULE_NAME", module_name) for a in hatch_build["artifacts"]
+    ]
+    result["tool"]["hatch"]["build"]["only-packages"] = hatch_build["only-packages"]
 
-    # Set packages if not already set
+    if "targets" not in result["tool"]["hatch"]["build"]:
-    if "packages" not in hatch_build:
+        result["tool"]["hatch"]["build"]["targets"] = {}
-        hatch_build["packages"] = [
+
-            p.replace("MODULE_NAME", module_name) for p in hatch_additions["packages"]
+    result["tool"]["hatch"]["build"]["targets"]["sdist"] = hatch_build["targets"][
+        "sdist"
     ]
 
-    # Set artifacts if not already set
+    return result
-    if "artifacts" not in hatch_build:
-        hatch_build["artifacts"] = [
-            a.replace("MODULE_NAME", module_name) for a in hatch_additions["artifacts"]
-        ]
-
-    # Set only-packages if not already set
-    if "only-packages" not in hatch_build:
-        hatch_build["only-packages"] = hatch_additions["only-packages"]
-
-    # Add sdist target with custom hook
-    if "targets" not in hatch_build:
-        hatch_build["targets"] = tomlkit.table()
-    if "sdist" not in hatch_build["targets"]:
-        hatch_build["targets"]["sdist"] = tomlkit.table()
-    if "hooks" not in hatch_build["targets"]["sdist"]:
-        hatch_build["targets"]["sdist"]["hooks"] = tomlkit.table()
-    if "custom" not in hatch_build["targets"]["sdist"]["hooks"]:
-        hatch_build["targets"]["sdist"]["hooks"]["custom"] = tomlkit.table()
-    if "path" not in hatch_build["targets"]["sdist"]["hooks"]["custom"]:
-        hatch_build["targets"]["sdist"]["hooks"]["custom"]["path"] = hatch_additions[
-            "targets"
-        ]["sdist"]["hooks"]["custom"]["path"]
-
-    return data
 
 
 # =============================================================================
@@ -790,6 +521,8 @@ def find_js_runtime() -> tuple[str, str] | None:
     Returns (tool_path, tool_name) where tool_name is "deno", "npm", or "bun".
     Returns None if no runtime is found.
     """
+    import shutil
+
     options = ["deno", "npm", "bun"]
 
     # Check for JS_RUNTIME environment variable
@@ -951,9 +684,7 @@ def cmd_setup(args: argparse.Namespace) -> int:
     fastapi_vue_scripts = scripts_dir / "fastapi-vue"
 
     # Find existing FastAPI app
-    app_info = (
+    app_info = find_fastapi_app(module_dir) if module_dir.exists() else None
-        find_fastapi_app(module_dir, project_dir) if module_dir.exists() else None
-    )
 
     if app_info:
         app_file, app_var = app_info
@@ -969,50 +700,30 @@ def cmd_setup(args: argparse.Namespace) -> int:
 
     # Create directories
     if not dry_run:
+        fastapi_vue_scripts.mkdir(parents=True, exist_ok=True)
         if not module_dir.exists():
             module_dir.mkdir(parents=True)
-        fastapi_vue_scripts.mkdir(parents=True, exist_ok=True)
 
     # === Install scripts (always update our own scripts) ===
-    # Scripts in fastapi-vue folder are internal and always overwritten
+    script_files = [
-    # devserver.py can be customized, so use fallback if needed
+        (fastapi_vue_scripts / "util.py", "scripts/fastapi-vue/util.py"),
+        (
+            fastapi_vue_scripts / "build-frontend.py",
+            "scripts/fastapi-vue/build-frontend.py",
+        ),
+        (scripts_dir / "devserver.py", "scripts/devserver.py"),
+    ]
 
-    # Remove obsolete util.py if present
+    for dest_path, template_path in script_files:
-    obsolete_util = fastapi_vue_scripts / "util.py"
+        template = load_template(template_path)
-    if obsolete_util.exists():
-        if dry_run:
-            print(f"[DRY RUN] Would remove obsolete {obsolete_util}")
-        else:
-            obsolete_util.unlink()
-            print(f"🗑️  Removed obsolete {obsolete_util}")
-
-    # Copy all files from the template's fastapi-vue folder
-    template_fastapi_vue_dir = TEMPLATE_DIR / "scripts" / "fastapi-vue"
-    for template_file in template_fastapi_vue_dir.iterdir():
-        if template_file.is_file():
-            dest_path = fastapi_vue_scripts / template_file.name
-            template = template_file.read_text()
         content = render_template(template, **tpl_vars)
+        is_executable = dest_path.name == "devserver.py"
         write_file(
             dest_path,
             content,
             overwrite=True,
             dry_run=dry_run,
-                force=True,  # Internal files, always overwrite
+            executable=is_executable,
-            )
-
-    # devserver.py - use fallback if customized by user
-    devserver_path = scripts_dir / "devserver.py"
-    devserver_fallback = scripts_dir / "devserver.new.py"
-    template = load_template("scripts/devserver.py")
-    content = render_template(template, **tpl_vars)
-    write_file(
-        devserver_path,
-        content,
-        overwrite=True,
-        dry_run=dry_run,
-        executable=True,
-        fallback_path=devserver_fallback,
         )
 
     # === Handle app module ===
@@ -1036,31 +747,10 @@ def cmd_setup(args: argparse.Namespace) -> int:
 
     # === Handle __main__.py ===
     main_file = module_dir / "__main__.py"
-    main_fallback = module_dir / "__main__.new.py"
+    if not main_file.exists():
         template = load_template("backend/__main__.py")
-    main_content = render_template(template, **tpl_vars)
+        content = render_template(template, **tpl_vars)
-
+        write_file(main_file, content, overwrite=False, dry_run=dry_run)
-    # Check if project already has a CLI entrypoint in pyproject.toml
-    existing_cli = _find_existing_cli_entrypoint(project_dir, module_name)
-
-    if main_file.exists():
-        # File exists: update if it has the auto-upgrade marker, otherwise use fallback
-        write_file(
-            main_file,
-            main_content,
-            overwrite=True,
-            dry_run=dry_run,
-            fallback_path=main_fallback,
-        )
-    elif not existing_cli:
-        # No file and no existing entrypoint: create new __main__.py
-        write_file(
-            main_file,
-            main_content,
-            overwrite=False,
-            dry_run=dry_run,
-        )
-    # else: no file but has existing entrypoint - don't create (user has custom CLI setup)
 
     # === Update vite.config.js/ts ===
     frontend_dir = project_dir / "frontend"
@@ -1089,43 +779,39 @@ def cmd_setup(args: argparse.Namespace) -> int:
     # === Update pyproject.toml ===
     pyproject_path = project_dir / "pyproject.toml"
     if pyproject_path.exists():
-        old_content = pyproject_path.read_text()
+        with open(pyproject_path, "rb") as f:
-        data = tomlkit.parse(old_content)
+            data = tomllib.load(f)
 
         updated = merge_pyproject(data, PYPROJECT_ADDITIONS, module_name)
 
-        # Only add script entry if project doesn't already have scripts
+        # Add script entry pointing to the app we found/created
-        if "scripts" not in updated["project"] or not updated["project"]["scripts"]:
+        if "scripts" not in updated["project"]:
-            updated["project"]["scripts"] = tomlkit.table()
+            updated["project"]["scripts"] = {}
         script_name = module_name.replace("_", "-")
         updated["project"]["scripts"][script_name] = f"{module_name}.__main__:main"
 
-        # Check if content actually changed
+        if dry_run:
-        new_content = tomlkit.dumps(updated)
-
-        if new_content == old_content:
-            print(f"✔️  {pyproject_path} (already up to date)")
-        elif dry_run:
             print(f"[DRY RUN] Would update {pyproject_path}")
         else:
-            pyproject_path.write_text(new_content)
+            with open(pyproject_path, "wb") as f:
+                tomli_w.dump(updated, f)
             print(f"✅ Updated {pyproject_path}")
 
     # === Add dependencies using uv ===
     if dry_run:
-        print("[DRY RUN] Would run: uv add -U 'fastapi[standard]' fastapi-vue")
+        print("[DRY RUN] Would run: uv add 'fastapi[standard]' fastapi-vue")
-        print("[DRY RUN] Would run: uv add -U --group dev httpx")
+        print("[DRY RUN] Would run: uv add --group dev httpx")
     else:
         print("📦 Adding dependencies...")
         result = subprocess.run(
-            ["uv", "add", "-U", "fastapi[standard]", "fastapi-vue"],
+            ["uv", "add", "fastapi[standard]", "fastapi-vue"],
             cwd=project_dir,
             check=False,
         )
         if result.returncode != 0:
             print("⚠️  Failed to add main dependencies")
         result = subprocess.run(
-            ["uv", "add", "-U", "--group", "dev", "httpx"],
+            ["uv", "add", "--group", "dev", "httpx"],
             cwd=project_dir,
             check=False,
         )
@@ -1134,19 +820,17 @@ def cmd_setup(args: argparse.Namespace) -> int:
 
     # === Update .gitignore ===
     gitignore_path = project_dir / ".gitignore"
-    gitignore_entry = f"/{module_name}/frontend-build"
+    gitignore_entry = f"{module_name}/frontend-build/"
     if gitignore_path.exists():
-        gitignore_content = gitignore_path.read_bytes()
+        gitignore_content = gitignore_path.read_text()
-        if b"frontend-build" in gitignore_content:
+        if gitignore_entry not in gitignore_content:
-            print("✔️  .gitignore (frontend-build already ignored)")
+            if dry_run:
-        elif dry_run:
                 print(f"[DRY RUN] Would add {gitignore_entry} to .gitignore")
             else:
-            nl = b"\r\n" if b"\r\n" in gitignore_content else b"\n"
+                with open(gitignore_path, "a") as f:
-            suffix = b"" if gitignore_content.endswith(nl) else nl
+                    if not gitignore_content.endswith("\n"):
-            gitignore_path.write_bytes(
+                        f.write("\n")
-                gitignore_content + suffix + gitignore_entry.encode() + nl
+                    f.write(f"{gitignore_entry}\n")
-            )
                 print(f"✅ Added {gitignore_entry} to .gitignore")
     elif dry_run:
         print(f"[DRY RUN] Would create .gitignore with {gitignore_entry}")
@@ -1168,19 +852,6 @@ def cmd_setup(args: argparse.Namespace) -> int:
     )
     print(message)
 
-    # Show merge note if any .new.py files were written
-    if _new_files_written:
-        print()
-        print(
-            "⚠️  Note: Some files could not be auto-upgraded because you customized them."
-        )
-        print("   Please manually merge the following files:")
-        for new_file, original_file in _new_files_written:
-            print(f"     • {new_file.name} → {original_file.name}")
-        print()
-        # Clear the list for potential subsequent runs
-        _new_files_written.clear()
-
     return 0
 
 
@@ -1230,6 +901,11 @@ Examples:
     parser.add_argument(
         "--dry-run", action="store_true", help="Show what would be done"
     )
+    parser.add_argument(
+        "--version",
+        action="version",
+        version=f"%(prog)s {__version__}",
+    )
 
     args = parser.parse_args()
 

pyproject.toml

@@ -9,7 +9,7 @@ description = "Tool to create or patch FastAPI+Vue projects with integrated buil
 readme = "README.md"
 requires-python = ">=3.11"
 dependencies = [
-    "tomlkit>=0.12.0",
+    "tomli-w>=1.0.0",
 ]
 
 [project.urls]
@@ -22,6 +22,9 @@ fastapi-vue-setup = "fastapi_vue_setup:main"
 [tool.hatch.version]
 source = "vcs"
 
+[tool.hatch.build.hooks.vcs]
+version-file = "_version.py"
+
 [tool.hatch.build.targets.wheel]
 include = ["fastapi_vue_setup.py", "template/**/*", "_version.py"]
 

template/backend/__main__.py

@@ -1,26 +1,36 @@
-# auto-upgrade@fastapi-vue-setup - remove this if you modify this file
 import argparse
 import asyncio
 import os
 
+import uvicorn
 from fastapi_vue.hostutil import parse_endpoint
 from uvicorn import Config, Server
 
+from .APP_MODULE import APP_VAR
+
 DEFAULT_PORT = 5080
 
 
-def run_server(endpoints: list[dict], *, proxy=""):
+def run_server(endpoints: list[dict], *, proxy="", devmode=False):
     conf: dict[str, object] = {"app": "MODULE_NAME.APP_MODULE:APP_VAR"}
     if proxy:
         conf["proxy_headers"] = True
         conf["forwarded_allow_ips"] = proxy
+    if devmode:
+        conf["reload"] = True
+        conf["reload_dirs"] = ["MODULE_NAME"]
+        APP_VAR.debug = True
 
+    if len(endpoints) > 1:
+        # Run separate servers for multiple endpoints
         async def serve_all():
             async with asyncio.TaskGroup() as tg:
                 for ep in endpoints:
                     tg.create_task(Server(Config(**conf, **ep)).serve())
 
         asyncio.run(serve_all())
+    else:
+        uvicorn.run(**conf, **endpoints[0])
 
 
 def main():
@@ -35,10 +45,9 @@ def main():
     )
     args = parser.parse_args()
     proxy = os.getenv("FORWARDED_ALLOW_IPS", "127.0.0.1,::1")
-    try:
+    devmode = bool(os.getenv("FASTAPI_VUE_FRONTEND_URL"))
-        run_server(parse_endpoint(args.endpoint, DEFAULT_PORT), proxy=proxy)
+    endpoints = parse_endpoint(args.endpoint, DEFAULT_PORT)
-    except KeyboardInterrupt:
+    run_server(endpoints, proxy=proxy, devmode=devmode)
-        pass
 
 
 if __name__ == "__main__":

template/backend/app.py

@@ -5,7 +5,9 @@ from fastapi import FastAPI
 from fastapi_vue import Frontend
 
 # Vue Frontend static files
-frontend = Frontend(Path(__file__).with_name("frontend-build"), cached=["/assets/"])
+frontend = Frontend(
+    Path(__file__).with_name("frontend-build"), spa=True, cached=["/assets/"]
+)
 
 
 @asynccontextmanager
@@ -27,5 +29,5 @@ async def health_check():
     return {"status": "ok"}
 
 
-# Serve the Vue frontend (needs to be last if SPA catch-all is used)
+# Final catch-all route for frontend files (keep at end of file)
 frontend.route(app, "/")

template/scripts/devserver.py

@@ -1,64 +1,283 @@
 #!/usr/bin/env -S uv run
-# auto-upgrade@fastapi-vue-setup - remove this if you modify this file
+"""Run Vite development server for frontend and FastAPI backend with auto-reload.
-"""Run Vite development server for frontend and FastAPI backend with auto-reload."""
+
+Usage:
+    uv run scripts/devserver.py [host:port] [--backend host:port]
+
+The optional host:port argument sets where the Vite frontend listens.
+Supported forms: host[:port], :port (all interfaces), or just port.
+The --backend option sets where the FastAPI backend listens (default: localhost:5180).
+
+Environment:
+    JS_RUNTIME          Path or name of JS runtime to use (deno, npm/node or bun).
+    FASTAPI_VUE_FRONTEND_URL    Set by this script for the backend to know where Vite is.
+"""
 
 import argparse
 import asyncio
 import contextlib
+import ipaddress
 import os
-import sys
 from pathlib import Path
+from sys import stderr
+from urllib.parse import urlparse
 
-# Import util.py from scripts/fastapi-vue (not a package, so we adjust sys.path)
+import httpx
-sys.path.insert(0, str(Path(__file__).with_name("fastapi-vue")))
+
-from devutil import (  # type: ignore
+exec((Path(__file__).parent / "fastapi-vue/util.py").read_text("UTF-8"))  # noqa: S102
-    ProcessGroup,
+
-    logger,
+DEFAULT_HOST = "localhost"
-    ready,
+DEFAULT_VITE_PORT = 5173
-    setup_fastapi,
+DEFAULT_BACKEND_PORT = 5180
-    setup_vite,
+FRONTEND_PATH = Path(__file__).parent.parent / "frontend"
-)
+
+EPILOG = """
+  scripts/devserver.py                       # Default ports on localhost
+  scripts/devserver.py 3000                  # Vite on localhost:3000
+  scripts/devserver.py :3000 --backend 8000  # *:3000, localhost:8000
+"""
+
+BUN_BUG = """\
+┃ ⚠️  Bun cannot correctly proxy API requests to the backend.
+┃ Bug report: https://github.com/oven-sh/bun/issues/9882
+┃
+┃ Consider using deno or npm instead for development.
+"""
 
 
-async def run_devserver(frontend: str, backend: str) -> None:
+def parse_endpoint(
-    reporoot = Path(__file__).parent.parent
+    value: str | None, default_port: int = DEFAULT_VITE_PORT
-    front = reporoot / "frontend"
+) -> tuple[str | None, int, bool]:
-    if not (front / "package.json").exists():
+    """Parse an endpoint for Vite or backend.
-        logger.warning("Frontend source not found at %s", front)
+
+    Returns (host, port, all_ifaces).
+    """
+    if not value:
+        return DEFAULT_HOST, default_port, False
+
+    # Port only (numeric) -> localhost:port
+    if value.isdigit():
+        return DEFAULT_HOST, int(value), False
+
+    # Leading colon :port -> bind all interfaces
+    if value.startswith(":") and value != ":":
+        port_part = value[1:]
+        if not port_part.isdigit():
+            raise SystemExit(f"Invalid port in '{value}'")
+        return None, int(port_part), True
+
+    # Unbracketed IPv6 (cannot safely contain a port)
+    if value.count(":") > 1 and not value.startswith("["):
+        try:
+            ipaddress.IPv6Address(value)
+        except ValueError as e:
+            raise SystemExit(f"Invalid IPv6 address '{value}': {e}") from e
+        return value, default_port, False
+
+    # Use urllib.parse for everything else
+    parsed = urlparse(f"//{value}")
+    host = parsed.hostname or DEFAULT_HOST
+    port = parsed.port or default_port
+
+    return host, port, False
+
+
+def resolve_frontend_tools(
+    vite_host: str | None, vite_port: int, all_ifaces: bool
+) -> tuple[list[str], list[str], str]:
+    """Resolve frontend install and dev commands.
+
+    Returns (install_cmd, dev_cmd, tool_name).
+    Raises SystemExit if tools are not available.
+    """
+    if not (FRONTEND_PATH / "package.json").exists():
+        stderr.write(f"┃ ⚠️  Frontend source not found at {FRONTEND_PATH}\n")
         raise SystemExit(1)
 
-    frontend_url, npm_install, vite = setup_vite(frontend)
+    result = find_js_runtime()  # noqa # type: ignore
-    backend_url, fastapi = setup_fastapi(backend, "MODULE_NAME.APP_MODULE:APP_VAR")
+    if result is None:
+        if not os.environ.get("JS_RUNTIME"):
+            stderr.write("┃ ⚠️  deno, npm or bun needed to run the frontend server.\n")
+        raise SystemExit(1)
 
-    # Tell the everyone where the frontend and backend are (vite proxy, etc)
+    tool, name = result
-    os.environ["FASTAPI_VUE_FRONTEND_URL"] = frontend_url
-    os.environ["FASTAPI_VUE_BACKEND_URL"] = backend_url
 
-    async with ProcessGroup() as pg:
+    install_args = {
-        install_proc = await pg.spawn(*npm_install, cwd=front)
+        "deno": ("install", "--quiet", "--allow-scripts=npm:vue-demi"),
-        await asyncio.sleep(0.2)  # reduce message overlap
+        "npm": ("install", "--silent"),
-        await pg.spawn(
+        "bun": ("install", "--silent"),
-            *fastapi,
+    }
-            "--reload",
+    dev_args = {
-            "--reload-dir=MODULE_NAME",  # Don't reload on frontend changes
+        "deno": ("run", "dev", "--"),
-            "--forwarded-allow-ips=*",
+        "npm": ("--silent", "run", "dev", "--"),
-            cwd=reporoot,
+        "bun": ("run", "dev", "--"),
+    }
+
+    install_cmd = [tool, *install_args[name]]
+    dev_cmd = [
+        tool,
+        *dev_args[name],
+        "--clearScreen=false",
+        f"--port={vite_port}",
+    ]
+
+    if all_ifaces:
+        dev_cmd.append("--host")
+    elif vite_host and vite_host != "localhost":
+        dev_cmd.append(f"--host={vite_host}")
+
+    if name == "bun":
+        stderr.write(BUN_BUG)
+
+    return install_cmd, dev_cmd, name
+
+
+async def wait_for_backend(backend_host: str, backend_port: int):
+    """Wait for the backend to be ready by polling the health endpoint."""
+    max_attempts = 50
+    async with httpx.AsyncClient() as client:
+        for attempt in range(max_attempts):
+            try:
+                await client.get(f"http://{backend_host}:{backend_port}", timeout=1.0)
+                stderr.write("✓ Backend ready!\n")
+                return True
+            except httpx.RequestError:
+                if attempt == max_attempts - 1:
+                    stderr.write("┃ ⚠️  Backend didn't start in time\n")
+                    return False
+                await asyncio.sleep(0.1)
+    return False
+
+
+async def _terminate_process(proc: asyncio.subprocess.Process, name: str) -> None:
+    """Gracefully terminate a subprocess."""
+    if proc.returncode is not None:
+        return
+    try:
+        proc.terminate()
+    except ProcessLookupError:
+        return
+    try:
+        await asyncio.wait_for(proc.wait(), timeout=2)
+    except TimeoutError:
+        try:
+            proc.kill()
+        except ProcessLookupError:
+            return
+        await proc.wait()
+
+
+async def run_devserver(
+    vite_host: str | None,
+    vite_port: int,
+    all_ifaces: bool,
+    backend_host: str,
+    backend_port: int,
+) -> None:
+    """Run the development server with install, backend, and frontend."""
+    install_cmd, dev_cmd, tool_name = resolve_frontend_tools(
+        vite_host, vite_port, all_ifaces
     )
 
-        # Wait for both install and backend to be ready
+    # Tell the backend where the Vite dev server is
-        async with asyncio.TaskGroup() as tg:
+    os.environ["FASTAPI_VUE_FRONTEND_URL"] = (
-            tg.create_task(pg.wait(install_proc))
+        f"http://{vite_host or 'localhost'}:{vite_port}"
-            tg.create_task(ready(backend_url, path="/api/health?from=devserver.py"))
+    )
+    # Tell Vite where the backend is (for proxying /api requests)
+    os.environ["FASTAPI_VUE_BACKEND_URL"] = f"http://{backend_host}:{backend_port}"
+    cwd = str(Path(__file__).parent.parent)
+    frontend_cwd = str(FRONTEND_PATH)
 
-        # Start Vite dev server (ProcessGroup waits for any exit, then terminates others)
+    backend_proc: asyncio.subprocess.Process | None = None
-        await pg.spawn(*vite, cwd=front)
+    install_proc: asyncio.subprocess.Process | None = None
+    frontend_proc: asyncio.subprocess.Process | None = None
+
+    try:
+        # Start install (concurrent with backend)
+        stderr.write(f">>> {tool_name} {' '.join(install_cmd[1:])}\n")
+        install_proc = await asyncio.create_subprocess_exec(
+            *install_cmd, cwd=frontend_cwd
+        )
+
+        await asyncio.sleep(0.1)
+
+        # Start backend (concurrent with install)
+        backend_cmd = [
+            "uvicorn",
+            "MODULE_NAME.app:app",
+            "--host",
+            backend_host,
+            "--port",
+            str(backend_port),
+            "--reload",
+        ]
+        stderr.write(f">>> {' '.join(backend_cmd)}\n")
+        backend_proc = await asyncio.create_subprocess_exec(*backend_cmd, cwd=cwd)
+
+        # Wait for install to complete and backend to be ready
+        install_task = asyncio.create_task(install_proc.wait(), name="install")
+        backend_ready_task = asyncio.create_task(
+            wait_for_backend(backend_host, backend_port), name="backend_ready"
+        )
+
+        done, pending = await asyncio.wait(
+            {install_task, backend_ready_task},
+            return_when=asyncio.FIRST_COMPLETED,
+        )
+
+        for task in done:
+            if task.get_name() == "install":
+                if task.result() != 0:
+                    stderr.write("┃ ⚠️  Install failed\n")
+                    raise SystemExit(1)
+            elif task.get_name() == "backend_ready" and not task.result():
+                raise SystemExit(1)
+
+        if pending:
+            done2, _ = await asyncio.wait(pending)
+            for task in done2:
+                if task.get_name() == "install":
+                    if task.result() != 0:
+                        stderr.write("┃ ⚠️  Install failed\n")
+                        raise SystemExit(1)
+                elif task.get_name() == "backend_ready" and not task.result():
+                    raise SystemExit(1)
+
+        install_proc = None
+
+        # Start Vite dev server
+        stderr.write(f">>> {tool_name} {' '.join(dev_cmd[1:])}\n")
+        frontend_proc = await asyncio.create_subprocess_exec(*dev_cmd, cwd=frontend_cwd)
+
+        # Wait for either process to exit
+        done, pending = await asyncio.wait(
+            {
+                asyncio.create_task(backend_proc.wait(), name="backend"),
+                asyncio.create_task(frontend_proc.wait(), name="frontend"),
+            },
+            return_when=asyncio.FIRST_COMPLETED,
+        )
+        for t in done:
+            t.result()
+        for t in pending:
+            t.cancel()
+
+    except asyncio.CancelledError:
+        stderr.write("\n✓ Shutting down...\n")
+    finally:
+        if frontend_proc is not None:
+            await _terminate_process(frontend_proc, "frontend")
+        if install_proc is not None:
+            await _terminate_process(install_proc, "install")
+        if backend_proc is not None:
+            await _terminate_process(backend_proc, "backend")
 
 
 def main():
     parser = argparse.ArgumentParser(
         description="Run Vite and FastAPI development servers",
         formatter_class=argparse.RawDescriptionHelpFormatter,
-        epilog=HELP_EPILOG,
+        epilog=EPILOG,
     )
     parser.add_argument(
         "frontend",
@@ -72,17 +291,16 @@ def main():
         help="FastAPI backend endpoint (default: localhost:5180)",
     )
     args = parser.parse_args()
+
+    vite_host, vite_port, all_ifaces = parse_endpoint(args.frontend, DEFAULT_VITE_PORT)
+    backend_host, backend_port, _ = parse_endpoint(args.backend, DEFAULT_BACKEND_PORT)
+    # Backend host defaults to localhost (never None)
+    backend_host = backend_host or DEFAULT_HOST
+
     with contextlib.suppress(KeyboardInterrupt):
-        asyncio.run(run_devserver(args.frontend, args.backend))
+        asyncio.run(
-
+            run_devserver(vite_host, vite_port, all_ifaces, backend_host, backend_port)
-
+        )
-HELP_EPILOG = """
-  scripts/devserver.py                       # Default ports on localhost
-  scripts/devserver.py 3000                  # Vite on localhost:3000
-  scripts/devserver.py :3000 --backend 8000  # *:3000, localhost:8000
-
-  JS_RUNTIME environment variable can be used to select the JS runtime
-"""
 
 
 if __name__ == "__main__":

template/scripts/fastapi-vue/build-frontend.py

@@ -1,15 +1,34 @@
 """Hatch build hook for building Vue frontend during package build."""
 
-import sys
+import subprocess
 from pathlib import Path
+from sys import stderr
 
 from hatchling.builders.hooks.plugin.interface import BuildHookInterface  # type: ignore
 
-sys.path.insert(0, str(Path(__file__).parent))
+exec(Path(__file__).with_name("util.py").read_text("UTF-8"))  # noqa: S102
-from buildutil import build
+
+
+def run(cmd, **kwargs):
+    """Run a command and display it."""
+    display_cmd = [Path(cmd[0]).name, *cmd[1:]]
+    stderr.write(f"### {' '.join(display_cmd)}\n")
+    subprocess.run(cmd, check=True, **kwargs)
 
 
 class CustomBuildHook(BuildHookInterface):
+    """Build hook that compiles Vue frontend before packaging."""
+
     def initialize(self, version, build_data):
         super().initialize(version, build_data)
-        build("frontend")
+        stderr.write(">>> Building the frontend\n")
+
+        install_cmd, build_cmd = find_build_tool()  # noqa # type: ignore
+
+        try:
+            run(install_cmd, cwd="frontend")
+            stderr.write("\n")
+            run(build_cmd, cwd="frontend")
+        except Exception as e:
+            stderr.write(f"Error occurred while building frontend: {e}\n")
+            raise

template/scripts/fastapi-vue/util.py

@@ -0,0 +1,87 @@
+"""Shared utilities for build and dev scripts."""
+
+import os
+import shutil
+from pathlib import Path
+from sys import stderr
+
+
+def find_js_runtime() -> tuple[str, str] | None:
+    """Find a JavaScript runtime from JS_RUNTIME env or auto-detect.
+
+    Returns (tool_path, tool_name) where tool_name is "deno", "npm", or "bun".
+    Returns None if no runtime is found.
+    """
+    options = ["deno", "npm", "bun"]
+
+    # Check for JS_RUNTIME environment variable
+    if js_runtime_env := os.environ.get("JS_RUNTIME"):
+        js_runtime = js_runtime_env
+        js_path = Path(js_runtime)
+        runtime_name = js_path.name
+        # Map node to npm
+        if runtime_name == "node":
+            runtime_name = "npm"
+            js_runtime = str(js_path.parent / "npm") if js_path.parent.name else "npm"
+        for option in options:
+            if option == runtime_name or runtime_name.startswith(option):
+                tool = shutil.which(js_runtime)
+                if tool is None:
+                    stderr.write(f"┃ ⚠️  JS_RUNTIME={js_runtime_env} not found\n")
+                    return None
+                return tool, option
+        stderr.write(f"┃ ⚠️  JS_RUNTIME={js_runtime_env} not recognized\n")
+        return None
+
+    # Auto-detect
+    for option in options:
+        if tool := shutil.which(option):
+            return tool, option
+    return None
+
+
+def find_build_tool():
+    """Find JavaScript runtime and construct install/build commands.
+
+    Returns (install_cmd, build_cmd) tuples of command lists.
+    Raises RuntimeError if no runtime is found.
+    """
+    install = {
+        "deno": ("install", "--allow-scripts=npm:vue-demi"),
+        "npm": ("install",),
+        "bun": ("--bun", "install"),
+    }
+    # Run vite directly for deno to avoid npm-run-all2/run-p issues
+    build = {
+        "deno": ("run", "-A", "npm:vite", "build"),
+        "npm": ("run", "build"),
+        "bun": ("--bun", "run", "build"),
+    }
+
+    result = find_js_runtime()
+    if result is None:
+        raise RuntimeError(
+            "Deno, npm or Bun is required for building but none was found"
+        )
+
+    tool, name = result
+    return [tool, *install[name]], [tool, *build[name]]
+
+
+def find_dev_tool():
+    """Find JavaScript runtime and construct dev command.
+
+    Returns (dev_cmd, tool_name) or (None, None) if not found.
+    """
+    dev_args = {
+        "deno": ("run", "dev", "--"),
+        "npm": ("--silent", "run", "dev", "--"),
+        "bun": ("run", "dev", "--"),
+    }
+
+    result = find_js_runtime()
+    if result is None:
+        return None, None
+
+    tool, name = result
+    return [tool, *dev_args[name]], name