diff --git a/libs/openant-core/parsers/javascript/unit_generator.js b/libs/openant-core/parsers/javascript/unit_generator.js
index 7b76219c..c2f8ee51 100644
--- a/libs/openant-core/parsers/javascript/unit_generator.js
+++ b/libs/openant-core/parsers/javascript/unit_generator.js
@@ -49,6 +49,11 @@ const fs = require('fs');
 const path = require('path');
 const { DependencyResolver } = require('./dependency_resolver');
 
+// File boundary marker for enhanced code (module-level for parity with the
+// python/php/c/ruby parsers, so external consumers can import the canonical
+// marker instead of re-defining it and risking silent drift).
+const FILE_BOUNDARY = '\n\n// ========== File Boundary ==========\n\n';
+
 class UnitGenerator {
     constructor(repoPath, datasetName = null, options = {}) {
         this.repoPath = repoPath;
@@ -162,7 +167,6 @@ class UnitGenerator {
      * Matches DVNA enhanced dataset format expected by experiment.py
      */
     _assembleEnhancedCode(funcData, upstreamDependencies, downstreamCallers) {
-        const FILE_BOUNDARY = '\n\n// ========== File Boundary ==========\n\n';
         const parts = [];
         const includedCode = new Set();
 
@@ -479,4 +483,4 @@ if (require.main === module) {
     }
 }
 
-module.exports = { UnitGenerator };
+module.exports = { UnitGenerator, FILE_BOUNDARY };
diff --git a/libs/openant-core/tests/parsers/javascript/test_unit_generator_file_boundary.py b/libs/openant-core/tests/parsers/javascript/test_unit_generator_file_boundary.py
new file mode 100644
index 00000000..239df081
--- /dev/null
+++ b/libs/openant-core/tests/parsers/javascript/test_unit_generator_file_boundary.py
@@ -0,0 +1,71 @@
+"""Tests for FILE_BOUNDARY module-level export parity in the JS unit generator.
+
+The JavaScript parser declared FILE_BOUNDARY as a
+function-local `const` inside `_assembleEnhancedCode` and never exported it,
+unlike the python/php/c/ruby parsers which expose it as a module-level constant
+(python/unit_generator.py:60, php/c/ruby :35). That made the canonical boundary
+marker un-importable and risked silent drift across language parsers.
+
+These exercise the JS module's exports by running Node.js as a subprocess
+(mirroring tests/parsers/javascript/test_express_route_handlers.py). They skip
+when Node.js or the parser's npm dependencies aren't installed.
+"""
+import json
+import shutil
+import subprocess
+from pathlib import Path
+
+import pytest
+
+
+PARSERS_JS_DIR = Path(__file__).parent.parent.parent.parent / "parsers" / "javascript"
+NODE_MODULES = PARSERS_JS_DIR / "node_modules"
+UNIT_GENERATOR_JS = PARSERS_JS_DIR / "unit_generator.js"
+
+# Canonical boundary marker shared with the python/php/c/ruby parsers.
+# (Comment syntax differs by language: JS/PHP/C/Zig use `//`, python/ruby use `#`.)
+EXPECTED_FILE_BOUNDARY = "\n\n// ========== File Boundary ==========\n\n"
+
+pytestmark = pytest.mark.skipif(
+    not shutil.which("node") or not NODE_MODULES.exists(),
+    reason="Node.js or JS parser npm dependencies not available",
+)
+
+
+def _require_exports() -> dict:
+    """require() the module in Node and return its exports as JSON."""
+    script = (
+        f"const m = require({json.dumps(str(UNIT_GENERATOR_JS))});"
+        "process.stdout.write(JSON.stringify({"
+        "keys: Object.keys(m),"
+        "fileBoundaryType: typeof m.FILE_BOUNDARY,"
+        "fileBoundary: m.FILE_BOUNDARY === undefined ? null : m.FILE_BOUNDARY,"
+        "}));"
+    )
+    result = subprocess.run(
+        ["node", "-e", script], capture_output=True, text=True, timeout=30
+    )
+    assert result.returncode == 0, (
+        f"node require() failed:\nstdout={result.stdout}\nstderr={result.stderr}"
+    )
+    return json.loads(result.stdout)
+
+
+def test_FILE_BOUNDARY_exported():
+    """FILE_BOUNDARY must be a module-level export (importable by other modules)."""
+    exports = _require_exports()
+    assert "FILE_BOUNDARY" in exports["keys"], (
+        "FILE_BOUNDARY is not exported from unit_generator.js; "
+        f"module.exports keys = {exports['keys']}"
+    )
+
+
+def test_FILE_BOUNDARY_is_string():
+    """The exported FILE_BOUNDARY must be the canonical boundary marker string."""
+    exports = _require_exports()
+    assert exports["fileBoundaryType"] == "string", (
+        f"FILE_BOUNDARY should be a string, got type {exports['fileBoundaryType']!r}"
+    )
+    assert exports["fileBoundary"] == EXPECTED_FILE_BOUNDARY, (
+        f"FILE_BOUNDARY value mismatch: {exports['fileBoundary']!r}"
+    )