DOP-4060 adds language selector to unified footer on docs' pages.

src/components/DocumentBody.js

@@ -1,4 +1,4 @@
-import React, { useState } from 'react';
+import React, { useState, useEffect } from 'react';
 import PropTypes from 'prop-types';
 import { UnifiedFooter } from '@mdb/consistent-nav';
 import { usePresentationMode } from '../hooks/use-presentation-mode';
@@ -9,6 +9,7 @@ import { getMetaFromDirective } from '../utils/get-meta-from-directive';
 import { getPlaintext } from '../utils/get-plaintext';
 import { getTemplate } from '../utils/get-template';
 import useSnootyMetadata from '../utils/use-snooty-metadata';
+import { isBrowser } from '../utils/is-browser';
 import Widgets from './Widgets';
 import SEO from './SEO';
 import FootnoteContext from './Footnote/footnote-context';
@@ -68,10 +69,29 @@ const getAnonymousFootnoteReferences = (index, numAnonRefs) => {
 };
 
 const DocumentBody = (props) => {
+  const HIDE_UNIFIED_FOOTER_LOCALE = process.env['GATSBY_HIDE_UNIFIED_FOOTER_LOCALE'] === 'true';
+
   const {
     location,
     pageContext: { page, slug, template },
   } = props;
+
+  useEffect(() => {
+    // A workaround to remove the other locale options.
+    if (!HIDE_UNIFIED_FOOTER_LOCALE) {
+      const footer = document.getElementById('footer-container');
+      const footerUlElement = footer?.querySelector('ul');
+      if (footerUlElement) {
+        // For DOP-4060 we only want to support English and Simple Chinese (for now)
+        const en = footerUlElement.firstChild;
+        const simpleChinese = footerUlElement.lastChild;
+        footerUlElement.innerHTML = null;
+        footerUlElement.appendChild(en);
+        footerUlElement.appendChild(simpleChinese);
+      }
+    }
+  }, [HIDE_UNIFIED_FOOTER_LOCALE]);
+
   const initialization = () => {
     const pageNodes = getNestedValue(['children'], page) || [];
     const footnotes = getFootnotes(pageNodes);
@@ -90,6 +110,17 @@ const DocumentBody = (props) => {
 
   const isInPresentationMode = usePresentationMode()?.toLocaleLowerCase() === 'true';
 
+  const onSelectLocale = (locale) => {
+    const localeHrefMap = {
+      'zh-cn': 'https://mongodbcom-cdn.website.staging.corp.mongodb.com/zh-cn/docs-qa/',
+      'en-us': 'https://mongodbcom-cdn.website.staging.corp.mongodb.com/docs-qa/,',
+    };
+
+    if (isBrowser) {
+      window.location.href = localeHrefMap[locale];
+    }
+  };
+
   return (
     <>
       <Widgets
@@ -109,8 +140,8 @@ const DocumentBody = (props) => {
         </FootnoteContext.Provider>
       </Widgets>
       {!isInPresentationMode && (
-        <div data-testid="consistent-footer">
-          <UnifiedFooter hideLocale={true} />
+        <div data-testid="consistent-footer" id="footer-container">
+          <UnifiedFooter hideLocale={HIDE_UNIFIED_FOOTER_LOCALE} onSelectLocale={onSelectLocale} />
         </div>
       )}
     </>

tests/unit/Presentation.test.js

@@ -10,6 +10,9 @@ jest.mock(`../../src/utils/use-snooty-metadata`, () => {
 });
 
 describe('DocumentBody', () => {
+  beforeAll(() => {
+    jest.spyOn(document, 'querySelector');
+  });
   it('renders the necessary elements', () => {
     mockLocation(null);
     render(<DocumentBody location={window.location} pageContext={mockPageContext} />);
@@ -18,6 +21,12 @@ describe('DocumentBody', () => {
     expect(footer).toBeVisible();
     expect(footer).toMatchSnapshot();
 
+    if (!process.env.GATSBY_HIDE_UNIFIED_FOOTER_LOCALE) {
+      const languageSelector = screen.getByTestId('options');
+      expect(languageSelector).toBeInTheDocument();
+      expect(languageSelector.querySelectorAll('li')).toHaveLength(2);
+    }
+
     const feedbackWidget = screen.getByText('Share Feedback');
     expect(feedbackWidget).toBeVisible();
     expect(feedbackWidget).toMatchSnapshot();