fix: slugFormatter populates date template variables using date from entry if it exists

packages/decap-cms-core/src/lib/__tests__/formatters.spec.js

@@ -274,8 +274,8 @@ describe('formatters', () => {
   };
 
   describe('slugFormatter', () => {
-    const date = new Date('2020-01-01');
-    jest.spyOn(global, 'Date').mockImplementation(() => date);
+    const date = new Date('2020-01-01').valueOf();
+    Date.now = jest.spyOn(Date, 'now').mockImplementation(() => date);
 
     const { selectIdentifier } = require('../../reducers/collections');
 
@@ -312,6 +312,34 @@ describe('formatters', () => {
       ).toBe('entry-slug');
     });
 
+    it('should see date filters applied to date from entry if it exists', () => {
+      const { selectInferredField } = require('../../reducers/collections');
+      selectInferredField.mockReturnValue('date');
+      const entryDate = new Date('2026-10-20');
+
+      expect(
+        slugFormatter(
+          Map({ slug: '{{year}}-{{month}}-{{day}}-{{title}}' }),
+          Map({ date: entryDate, title: 'post title' }),
+          slugConfig,
+        ),
+      ).toBe('2026-10-20-post-title');
+    });
+
+    it('should see date filters applied to publishDate from entry if it exists', () => {
+      const { selectInferredField } = require('../../reducers/collections');
+      selectInferredField.mockReturnValue('publishDate');
+      const entryDate = new Date('2026-10-20');
+
+      expect(
+        slugFormatter(
+          Map({ slug: '{{year}}-{{month}}-{{day}}-{{title}}' }),
+          Map({ publishDate: entryDate, title: 'post title' }),
+          slugConfig,
+        ),
+      ).toBe('2026-10-20-post-title');
+    });
+
     it('should return slug', () => {
       selectIdentifier.mockReturnValueOnce('title');
 

packages/decap-cms-core/src/lib/formatters.ts

@@ -21,6 +21,7 @@ import type { Map } from 'immutable';
 const {
   compileStringTemplate,
   parseDateFromEntry,
+  parseDateFromEntryData,
   SLUG_MISSING_REQUIRED_DATE,
   keyToPathArray,
   addFileTemplateFields,
@@ -129,7 +130,11 @@ export function slugFormatter(
   }
 
   const processSegment = getProcessSegment(slugConfig);
-  const date = new Date();
+  const date =
+    parseDateFromEntryData(
+      entryData as unknown as Map<string, unknown>,
+      selectInferredField(collection, 'date'),
+    ) || new Date(Date.now());
   const slug = compileStringTemplate(slugTemplate, date, identifier, entryData, processSegment);
 
   if (!collection.has('path')) {

packages/decap-cms-core/src/reducers/__tests__/collections.spec.js

@@ -11,6 +11,7 @@ import collections, {
   getFieldsNames,
   selectField,
   updateFieldByKey,
+  selectInferredField,
 } from '../collections';
 import { FILES, FOLDER } from '../../constants/collectionTypes';
 
@@ -568,4 +569,42 @@ describe('collections', () => {
       );
     });
   });
+
+  describe("selectInferredField(collection, 'date')", () => {
+    it('should return publishDate if set', () => {
+      const collection = fromJS({
+        fields: [{ name: 'title' }, { name: 'publishDate', widget: 'datetime' }],
+      });
+
+      expect(selectInferredField(collection, 'date')).toEqual('publishDate');
+    });
+
+    it('should return publish_date if set', () => {
+      const collection = fromJS({
+        fields: [{ name: 'title' }, { name: 'publish_date', widget: 'datetime' }],
+      });
+
+      expect(selectInferredField(collection, 'date')).toEqual('publish_date');
+    });
+
+    it('should return date if set', () => {
+      const collection = fromJS({
+        fields: [{ name: 'title' }, { name: 'date', widget: 'datetime' }],
+      });
+
+      expect(selectInferredField(collection, 'date')).toEqual('date');
+    });
+
+    it('should return first date field if multiple synonyms are present', () => {
+      const collection = fromJS({
+        fields: [
+          { name: 'title' },
+          { name: 'publishDate', widget: 'datetime' },
+          { name: 'date', widget: 'datetime' },
+        ],
+      });
+
+      expect(selectInferredField(collection, 'date')).toEqual('publishDate');
+    });
+  });
 });

packages/decap-cms-lib-widgets/src/stringTemplate.ts

@@ -61,7 +61,18 @@ export function parseDateFromEntry(entry: Map<string, unknown>, dateFieldName?:
     return;
   }
 
-  const dateValue = entry.getIn(['data', dateFieldName]);
+  const entryData = entry.getIn(['data']);
+  return parseDateFromEntryData(entryData, dateFieldName);
+}
+
+export function parseDateFromEntryData(
+  entryData: Map<string, unknown>,
+  dateFieldName?: string | null,
+) {
+  if (!dateFieldName) {
+    return;
+  }
+  const dateValue = entryData.getIn([dateFieldName]);
   const dateDayjs = dateValue && dayjs(dateValue);
   if (dateDayjs && dateDayjs.isValid()) {
     return dateDayjs.toDate();