TS migration. #2288. (#2328)

* Added TS. Updated build and linting config. Added types.

* [ts-migrate][.] Rename files from JS/JSX to TS/TSX

Co-authored-by: ts-migrate <>

* [ts-migrate][.] Run TS Migrate

Co-authored-by: ts-migrate <>

* Corrected files mangled by ts-migrate.

* Updated lint config, minor linting.

* Re-enabled Husky.

* Updated tests and config.

* Reverted webpack devtool config.

* Removed obsolete snapshots.

* Added annotations snap.

* Updated tsconfig includes wrt linting.

* Removed ts-migrate.

Co-authored-by: Timmy Huang <tihuan@users.noreply.github.com>

client/src/reducers/userInfo.js

@@ -1,26 +0,0 @@
-const UserInfo = (state = {}, action) => {
-  switch (action.type) {
-    case "initial data load start":
-      return {
-        ...state,
-        loading: true,
-        error: null,
-      };
-    case "userInfo load complete":
-      return {
-        ...state,
-        loading: false,
-        error: null,
-        ...action.userInfo,
-      };
-    case "initial data load error":
-      return {
-        ...state,
-        error: action.error,
-      };
-    default:
-      return state;
-  }
-};
-
-export default UserInfo;