diff --git a/packages/apostrophe/lib/compose-filters.js b/packages/apostrophe/lib/compose-filters.js
new file mode 100644
index 0000000000..cb3c724052
--- /dev/null
+++ b/packages/apostrophe/lib/compose-filters.js
@@ -0,0 +1,51 @@
+/**
+ * Shared utility for composing filters in doc-type and page modules.
+ *
+ * Transforms a filters object (keyed by name) into an array of filter
+ * definitions with normalized inputType, default values, and null choices.
+ *
+ * This was previously duplicated between:
+ * - @apostrophecms/doc-type/index.js composeFilters()
+ * - @apostrophecms/page/index.js composeFilters()
+ *
+ * @param {Object} filters - An object keyed by filter name, where each value
+ *   is a filter definition object.
+ * @returns {Array} An array of composed filter objects with `name` property added.
+ */
+module.exports = function composeFilters(filters) {
+  const composed = Object.entries(filters)
+    .map(([ name, filter ]) => ({
+      name,
+      ...filter,
+      inputType: filter.inputType || 'select'
+    }));
+
+  // Add a null choice if not already added or set to `required`
+  composed.forEach((filter) => {
+    if (Array.isArray(filter.choices)) {
+      if (
+        !filter.required &&
+        !filter.choices.find((choice) => choice.value === null)
+      ) {
+        filter.def = null;
+        filter.choices = filter.inputType === 'checkbox'
+          ? filter.choices
+          : filter.choices.concat({
+            value: null,
+            label: 'apostrophe:none'
+          });
+      }
+    } else {
+      // Dynamic choices from the REST API, but
+      // we need a label for "no opinion"
+      filter.nullLabel = filter.inputType === 'radio'
+        ? 'apostrophe:any'
+        : 'apostrophe:filterMenuChooseOne';
+    }
+    if (filter.inputType === 'checkbox') {
+      filter.def = [];
+    }
+  });
+
+  return composed;
+};
diff --git a/packages/apostrophe/modules/@apostrophecms/doc-type/index.js b/packages/apostrophe/modules/@apostrophecms/doc-type/index.js
index 3b3bde0f7d..ed0593c3b0 100644
--- a/packages/apostrophe/modules/@apostrophecms/doc-type/index.js
+++ b/packages/apostrophe/modules/@apostrophecms/doc-type/index.js
@@ -1675,40 +1675,7 @@ module.exports = {
       },
 
       composeFilters() {
-        // TODO: keep in sync with page/index.js composeFilters
-        self.filters = Object.entries(self.filters)
-          .map(([ name, filter ]) => ({
-            name,
-            ...filter,
-            inputType: filter.inputType || 'select'
-          }));
-
-        // Add a null choice if not already added or set to `required`
-        self.filters.forEach((filter) => {
-          if (Array.isArray(filter.choices)) {
-            if (
-              !filter.required &&
-              !filter.choices.find((choice) => choice.value === null)
-            ) {
-              filter.def = null;
-              filter.choices = filter.inputType === 'checkbox'
-                ? filter.choices
-                : filter.choices.concat({
-                  value: null,
-                  label: 'apostrophe:none'
-                });
-            }
-          } else {
-            // Dynamic choices from the REST API, but
-            // we need a label for "no opinion"
-            filter.nullLabel = filter.inputType === 'radio'
-              ? 'apostrophe:any'
-              : 'apostrophe:filterMenuChooseOne';
-          }
-          if (filter.inputType === 'checkbox') {
-            filter.def = [];
-          }
-        });
+        self.filters = require('../../../lib/compose-filters')(self.filters);
       },
 
       composeColumns() {
diff --git a/packages/apostrophe/modules/@apostrophecms/page/index.js b/packages/apostrophe/modules/@apostrophecms/page/index.js
index e68c45e975..e05b07326c 100644
--- a/packages/apostrophe/modules/@apostrophecms/page/index.js
+++ b/packages/apostrophe/modules/@apostrophecms/page/index.js
@@ -3304,40 +3304,7 @@ database.`);
         });
       },
       composeFilters() {
-        // TODO: keep in sync with doc-type/index.js composeFilters
-        self.filters = Object.entries(self.filters)
-          .map(([ name, filter ]) => ({
-            name,
-            ...filter,
-            inputType: filter.inputType || 'select'
-          }));
-
-        // Add a null choice if not already added or set to `required`
-        self.filters.forEach((filter) => {
-          if (Array.isArray(filter.choices)) {
-            if (
-              !filter.required &&
-              !filter.choices.find((choice) => choice.value === null)
-            ) {
-              filter.def = null;
-              filter.choices = filter.inputType === 'checkbox'
-                ? filter.choices
-                : filter.choices.concat({
-                  value: null,
-                  label: 'apostrophe:none'
-                });
-            }
-          } else {
-            // Dynamic choices from the REST API, but
-            // we need a label for "no opinion"
-            filter.nullLabel = filter.inputType === 'radio'
-              ? 'apostrophe:any'
-              : 'apostrophe:filterMenuChooseOne';
-          }
-          if (filter.inputType === 'checkbox') {
-            filter.def = [];
-          }
-        });
+        self.filters = require('../../../lib/compose-filters')(self.filters);
       },
       async getBatchArchivePatches(req, ids) {
         const batchReq = req.clone({