diff --git a/internal/pkg_web/BUILD.bazel b/internal/pkg_web/BUILD.bazel
index ecc9c9f683..6f11d63aaf 100644
--- a/internal/pkg_web/BUILD.bazel
+++ b/internal/pkg_web/BUILD.bazel
@@ -18,10 +18,10 @@ bzl_library(
 nodejs_binary(
     name = "assembler",
     data = [
-        "assembler.js",
+        "assembler.cjs",
         "//third_party/github.com/gjtorikian/isBinaryFile",
     ],
-    entry_point = ":assembler.js",
+    entry_point = ":assembler.cjs",
     # TODO: figure out why isbinaryfile isn't resolved properly
     templated_args = ["--bazel_patch_module_resolver"],
 )
@@ -29,11 +29,11 @@ nodejs_binary(
 # BEGIN-INTERNAL
 jasmine_node_test(
     name = "assembler_test",
-    srcs = ["assembler_spec.js"],
+    srcs = ["assembler_spec.cjs"],
     # TODO: figure out why isbinaryfile isn't resolved properly
     templated_args = ["--bazel_patch_module_resolver"],
     deps = [
-        "assembler.js",
+        "assembler.cjs",
         "//third_party/github.com/gjtorikian/isBinaryFile",
     ],
 )
@@ -43,6 +43,6 @@ filegroup(
     name = "package_contents",
     srcs = glob(
         ["*"],
-        exclude = ["*_spec.js"],
+        exclude = ["*_spec.cjs"],
     ),
 )
diff --git a/internal/pkg_web/assembler.js b/internal/pkg_web/assembler.cjs
similarity index 100%
rename from internal/pkg_web/assembler.js
rename to internal/pkg_web/assembler.cjs
diff --git a/internal/pkg_web/assembler_spec.js b/internal/pkg_web/assembler_spec.cjs
similarity index 97%
rename from internal/pkg_web/assembler_spec.js
rename to internal/pkg_web/assembler_spec.cjs
index 87ed896a03..e3f94fcfc0 100644
--- a/internal/pkg_web/assembler_spec.js
+++ b/internal/pkg_web/assembler_spec.cjs
@@ -1,4 +1,4 @@
-const assembler = require('./assembler');
+const assembler = require('./assembler.cjs');
 const path = require('path');
 const fs = require('fs');