fix: use string endsWith to filter by extension (#3097)

packages/netlify-cms-lib-util/src/__tests__/backendUtil.spec.js

@@ -1,4 +1,9 @@
-import { parseLinkHeader, getAllResponses, getPathDepth } from '../backendUtil';
+import {
+  parseLinkHeader,
+  getAllResponses,
+  getPathDepth,
+  filterByPropExtension,
+} from '../backendUtil';
 import { oneLine } from 'common-tags';
 import nock from 'nock';
 
@@ -79,3 +84,14 @@ describe('getPathDepth', () => {
     expect(getPathDepth('{{year}}/{{slug}}')).toBe(2);
   });
 });
+
+describe('filterByPropExtension', () => {
+  it('should return filtered array based on extension', () => {
+    expect(
+      filterByPropExtension('.html.md', 'path')([{ path: 'file.html.md' }, { path: 'file.json' }]),
+    ).toEqual([{ path: 'file.html.md' }]);
+    expect(
+      filterByPropExtension('html.md', 'path')([{ path: 'file.html.md' }, { path: 'file.json' }]),
+    ).toEqual([{ path: 'file.html.md' }]);
+  });
+});

packages/netlify-cms-lib-util/src/backendUtil.ts

@@ -1,14 +1,15 @@
 import { flow, fromPairs, get } from 'lodash';
 import { map } from 'lodash/fp';
 import { fromJS } from 'immutable';
-import { fileExtension } from './path';
 import unsentRequest from './unsentRequest';
 import APIError from './APIError';
 
 type Formatter = (res: Response) => Promise<string | Blob | unknown>;
 
 export const filterByPropExtension = (extension: string, propName: string) => <T>(arr: T[]) =>
-  arr.filter(el => fileExtension(get(el, propName)) === extension);
+  arr.filter(el =>
+    get(el, propName, '').endsWith(extension.startsWith('.') ? extension : `.${extension}`),
+  );
 
 const catchFormatErrors = (format: string, formatter: Formatter) => (res: Response) => {
   try {