diff --git a/packages/docusaurus-plugin-content-docs/src/sidebars/utils.ts b/packages/docusaurus-plugin-content-docs/src/sidebars/utils.ts
index 2f785a0320..e0d1152113 100644
--- a/packages/docusaurus-plugin-content-docs/src/sidebars/utils.ts
+++ b/packages/docusaurus-plugin-content-docs/src/sidebars/utils.ts
@@ -480,7 +480,7 @@ Available document ids are:
 
 export function toDocNavigationLink(
   doc: DocMetadataBase,
-  options?: {sidebarItemLabel?: string | undefined},
+  options?: {sidebarItemLabel?: string},
 ): PropNavigationLink {
   const {
     title,
diff --git a/packages/docusaurus-plugin-ideal-image/src/theme/IdealImageLegacy/components/helpers.js b/packages/docusaurus-plugin-ideal-image/src/theme/IdealImageLegacy/components/helpers.js
index f2c06f1602..5360a02721 100644
--- a/packages/docusaurus-plugin-ideal-image/src/theme/IdealImageLegacy/components/helpers.js
+++ b/packages/docusaurus-plugin-ideal-image/src/theme/IdealImageLegacy/components/helpers.js
@@ -86,7 +86,7 @@ export const bytesToSize = (bytes) => {
 const detectWebpSupport = () => {
   if (ssr) return false;
   const elem = document.createElement('canvas');
-  if (elem.getContext && elem.getContext('2d')) {
+  if (elem.getContext?.('2d')) {
     // was able or not to get WebP representation
     return elem.toDataURL('image/webp').indexOf('data:image/webp') === 0;
   } else {
@@ -97,8 +97,7 @@ const detectWebpSupport = () => {
 
 export const supportsWebp = detectWebpSupport();
 
-const isWebp = (x) =>
-  x.format === 'webp' || (x.src && x.src.match(/\.webp($|\?.*)/i));
+const isWebp = (x) => x.format === 'webp' || x.src?.match(/\.webp($|\?.*)/i);
 
 // eslint-disable-next-line no-shadow
 export const selectSrc = ({srcSet, maxImageWidth, supportsWebp}) => {
diff --git a/packages/docusaurus-theme-common/src/utils/useThemeConfig.ts b/packages/docusaurus-theme-common/src/utils/useThemeConfig.ts
index a1d095387e..af9fe2c825 100644
--- a/packages/docusaurus-theme-common/src/utils/useThemeConfig.ts
+++ b/packages/docusaurus-theme-common/src/utils/useThemeConfig.ts
@@ -15,7 +15,7 @@ export type DocsVersionPersistence = 'localStorage' | 'none';
 
 // TODO improve types, use unions
 export type NavbarItem = {
-  type?: string | undefined;
+  type?: string;
   items?: NavbarItem[];
   label?: string;
   position?: 'left' | 'right';
diff --git a/packages/docusaurus/src/commands/swizzle/__tests__/index.test.ts b/packages/docusaurus/src/commands/swizzle/__tests__/index.test.ts
index 013fbab245..a6bc0df605 100644
--- a/packages/docusaurus/src/commands/swizzle/__tests__/index.test.ts
+++ b/packages/docusaurus/src/commands/swizzle/__tests__/index.test.ts
@@ -91,13 +91,11 @@ async function createTestSite() {
     const siteThemePathPosix = posixPath(siteThemePath);
     expect(tree(siteThemePathPosix)).toMatchSnapshot('theme dir tree');
 
-    const files = (await Globby(siteThemePathPosix))
-      .map((file) => path.posix.relative(siteThemePathPosix, file))
-      .sort();
+    const files = await Globby('**/*', {cwd: siteThemePath});
 
     for (const file of files) {
       const fileContent = await fs.readFile(
-        path.posix.join(siteThemePath, file),
+        path.join(siteThemePath, file),
         'utf-8',
       );
       expect(fileContent).toMatchSnapshot(file);