diff --git a/client/src/client-only-routes/show-project-links.tsx b/client/src/client-only-routes/show-project-links.tsx
index 1522691d60..15ece65c64 100644
--- a/client/src/client-only-routes/show-project-links.tsx
+++ b/client/src/client-only-routes/show-project-links.tsx
@@ -32,7 +32,7 @@ type SolutionStateType = {
 const initSolutionState: SolutionStateType = {
   projectTitle: '',
   challengeFiles: null,
-  solution: null,
+  solution: '',
   isOpen: false
 };
 
@@ -156,10 +156,10 @@ const ShowProjectLinks = (props: IShowProjectLinksProps): JSX.Element => {
         </li>
       )
     );
-    /* eslint-disable @typescript-eslint/no-unsafe-assignment */
-    /* eslint-disable @typescript-eslint/no-unsafe-call */
-    /* eslint-disable @typescript-eslint/no-unsafe-return */
-    /* eslint-disable @typescript-eslint/no-unsafe-member-access */
+    /* eslint-enable @typescript-eslint/no-unsafe-assignment */
+    /* eslint-enable @typescript-eslint/no-unsafe-call */
+    /* eslint-enable @typescript-eslint/no-unsafe-return */
+    /* eslint-enable @typescript-eslint/no-unsafe-member-access */
   };
 
   const {
@@ -185,7 +185,9 @@ const ShowProjectLinks = (props: IShowProjectLinksProps): JSX.Element => {
           handleSolutionModalHide={handleSolutionModalHide}
           isOpen={isOpen}
           projectTitle={projectTitle}
-          solution={solution}
+          // 'solution' is theoretically never 'null', if it a JsAlgoData cert
+          // which is the only time we use the modal
+          solution={solution as undefined | string}
         />
       ) : null}
       <Trans i18nKey='certification.project.footnote'>
diff --git a/client/src/components/SolutionViewer/ProjectModal.js b/client/src/components/SolutionViewer/ProjectModal.tsx
similarity index 59%
rename from client/src/components/SolutionViewer/ProjectModal.js
rename to client/src/components/SolutionViewer/ProjectModal.tsx
index f12e3c9915..670a5b991f 100644
--- a/client/src/components/SolutionViewer/ProjectModal.js
+++ b/client/src/components/SolutionViewer/ProjectModal.tsx
@@ -1,34 +1,24 @@
 import { Button, Modal } from '@freecodecamp/react-bootstrap';
-import PropTypes from 'prop-types';
 import React from 'react';
 import { useTranslation } from 'react-i18next';
+import { ChallengeFiles } from '../../redux/prop-types';
 import SolutionViewer from './SolutionViewer';
 
-const propTypes = {
-  challengeFiles: PropTypes.array,
-  // TODO: removed once refactored to TS
-  //   PropTypes.shape({
-  //     contents: PropTypes.string,
-  //     ext: PropTypes.string,
-  //     key: PropTypes.string,
-  //     name: PropTypes.string,
-  //     path: PropTypes.string
-  //   })
-  // ),
-  handleSolutionModalHide: PropTypes.func,
-  isOpen: PropTypes.bool,
-  projectTitle: PropTypes.string,
-  solution: PropTypes.string
+type ProjectModalProps = {
+  challengeFiles: ChallengeFiles;
+  handleSolutionModalHide: () => void;
+  isOpen: boolean;
+  projectTitle: string;
+  solution?: string;
 };
 
-const ProjectModal = props => {
-  const {
-    isOpen,
-    projectTitle,
-    challengeFiles,
-    solution,
-    handleSolutionModalHide
-  } = props;
+const ProjectModal = ({
+  isOpen,
+  projectTitle,
+  challengeFiles,
+  solution,
+  handleSolutionModalHide
+}: ProjectModalProps): JSX.Element => {
   const { t } = useTranslation();
   return (
     <Modal
@@ -54,7 +44,6 @@ const ProjectModal = props => {
   );
 };
 
-ProjectModal.propTypes = propTypes;
 ProjectModal.displayName = 'ProjectModal';
 
 export default ProjectModal;
diff --git a/client/src/components/SolutionViewer/SolutionViewer.js b/client/src/components/SolutionViewer/SolutionViewer.js
deleted file mode 100644
index 34ab2db6af..0000000000
--- a/client/src/components/SolutionViewer/SolutionViewer.js
+++ /dev/null
@@ -1,70 +0,0 @@
-import { Panel } from '@freecodecamp/react-bootstrap';
-import Prism from 'prismjs';
-import PropTypes from 'prop-types';
-import React from 'react';
-
-const prismLang = {
-  css: 'css',
-  js: 'javascript',
-  jsx: 'javascript',
-  html: 'markup'
-};
-
-const SolutionViewer = ({
-  challengeFiles,
-  solution = '// The solution is not available for this project'
-}) =>
-  challengeFiles?.length ? (
-    challengeFiles.map(challengeFile => (
-      <Panel
-        bsStyle='primary'
-        className='solution-viewer'
-        key={challengeFile.ext}
-      >
-        <Panel.Heading>{challengeFile.ext.toUpperCase()}</Panel.Heading>
-        <Panel.Body>
-          <pre>
-            <code
-              className={`language-${prismLang[challengeFile.ext]}`}
-              dangerouslySetInnerHTML={{
-                __html: Prism.highlight(
-                  challengeFile.contents.trim(),
-                  Prism.languages[prismLang[challengeFile.ext]]
-                )
-              }}
-            />
-          </pre>
-        </Panel.Body>
-      </Panel>
-    ))
-  ) : (
-    <Panel
-      bsStyle='primary'
-      className='solution-viewer'
-      key={solution.slice(0, 10)}
-    >
-      <Panel.Heading>JS</Panel.Heading>
-      <Panel.Body>
-        <pre>
-          <code
-            className='language-markup'
-            dangerouslySetInnerHTML={{
-              __html: Prism.highlight(
-                solution.trim(),
-                Prism.languages.js,
-                'javascript'
-              )
-            }}
-          />
-        </pre>
-      </Panel.Body>
-    </Panel>
-  );
-
-SolutionViewer.displayName = 'SolutionViewer';
-SolutionViewer.propTypes = {
-  challengeFiles: PropTypes.array,
-  solution: PropTypes.string
-};
-
-export default SolutionViewer;
diff --git a/client/src/components/SolutionViewer/SolutionViewer.tsx b/client/src/components/SolutionViewer/SolutionViewer.tsx
new file mode 100644
index 0000000000..8c977096ac
--- /dev/null
+++ b/client/src/components/SolutionViewer/SolutionViewer.tsx
@@ -0,0 +1,67 @@
+import { Panel } from '@freecodecamp/react-bootstrap';
+import Prism from 'prismjs';
+import React from 'react';
+import { ChallengeFile, ChallengeFiles } from '../../redux/prop-types';
+
+type SolutionViewerProps = {
+  challengeFiles: ChallengeFiles;
+  solution?: string;
+};
+
+function SolutionViewer({
+  challengeFiles,
+  solution = '// The solution is not available for this project'
+}: SolutionViewerProps): JSX.Element {
+  return (
+    <>
+      {challengeFiles?.length ? (
+        challengeFiles.map((challengeFile: ChallengeFile) => (
+          <Panel
+            bsStyle='primary'
+            className='solution-viewer'
+            key={challengeFile}
+          >
+            <Panel.Heading>{challengeFile.ext.toUpperCase()}</Panel.Heading>
+
+            <Panel.Body>
+              <pre>
+                <code
+                  dangerouslySetInnerHTML={{
+                    __html: Prism.highlight(
+                      challengeFile.contents.trim(),
+                      Prism.languages[challengeFile.ext],
+                      ''
+                    )
+                  }}
+                />
+              </pre>
+            </Panel.Body>
+          </Panel>
+        ))
+      ) : (
+        <Panel
+          bsStyle='primary'
+          className='solution-viewer'
+          key={solution.slice(0, 10)}
+        >
+          <Panel.Heading>JS</Panel.Heading>
+          <Panel.Body>
+            <pre>
+              <code
+                className='language-markup'
+                dangerouslySetInnerHTML={{
+                  __html: Prism.highlight(
+                    solution.trim(),
+                    Prism.languages.js,
+                    'javascript'
+                  )
+                }}
+              />
+            </pre>
+          </Panel.Body>
+        </Panel>
+      )}
+    </>
+  );
+}
+export default SolutionViewer;