diff --git a/packages/babel-helper-skip-transparent-expression-wrappers/src/index.js b/packages/babel-helper-skip-transparent-expression-wrappers/src/index.ts
similarity index 66%
rename from packages/babel-helper-skip-transparent-expression-wrappers/src/index.js
rename to packages/babel-helper-skip-transparent-expression-wrappers/src/index.ts
index c218ac6c8fde..923fccd2087c 100644
--- a/packages/babel-helper-skip-transparent-expression-wrappers/src/index.js
+++ b/packages/babel-helper-skip-transparent-expression-wrappers/src/index.ts
@@ -1,14 +1,21 @@
-// @flow
-
 import * as t from "@babel/types";
 import type { NodePath } from "@babel/traverse";
 
+export type TransparentExprWrapper =
+  | t.TSAsExpression
+  | t.TSTypeAssertion
+  | t.TSNonNullExpression
+  | t.TypeCastExpression
+  | t.ParenthesizedExpression;
+
 // A transparent expression wrapper is an AST node that most plugins will wish
 // to skip, as its presence does not affect the behaviour of the code. This
 // includes expressions used for types, and extra parenthesis. For example, in
 // (a as any)(), this helper can be used to skip the TSAsExpression when
 // determining the callee.
-export function isTransparentExprWrapper(node: Node) {
+export function isTransparentExprWrapper(
+  node: t.Node,
+): node is TransparentExprWrapper {
   return (
     t.isTSAsExpression(node) ||
     t.isTSTypeAssertion(node) ||
@@ -18,10 +25,11 @@ export function isTransparentExprWrapper(node: Node) {
   );
 }
 
-export function skipTransparentExprWrappers(path: NodePath): NodePath {
+export function skipTransparentExprWrappers(
+  path: NodePath<t.Expression>,
+): NodePath<t.Expression> {
   while (isTransparentExprWrapper(path.node)) {
     path = path.get("expression");
   }
-
   return path;
 }
diff --git a/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/src/util.ts b/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/src/util.ts
index ebfdc8bebe55..c813c79a7281 100644
--- a/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/src/util.ts
+++ b/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/src/util.ts
@@ -22,7 +22,7 @@ function matchAffectedArguments(argumentNodes) {
 export function shouldTransform(
   path: NodePath<t.OptionalMemberExpression | t.OptionalCallExpression>,
 ): boolean {
-  let optionalPath = path;
+  let optionalPath: NodePath<t.Expression> = path;
   const chains = [];
   while (
     optionalPath.isOptionalMemberExpression() ||
diff --git a/tsconfig.json b/tsconfig.json
index c4ad33c2724b..a5cdfef327d9 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -20,6 +20,7 @@
     "./packages/babel-helper-optimise-call-expression/src/**/*.ts",
     "./packages/babel-helper-replace-supers/src/**/*.ts",
     "./packages/babel-helper-simple-access/src/**/*.ts",
+    "./packages/babel-helper-skip-transparent-expression-wrappers/src/**/*.ts",
     "./packages/babel-helper-split-export-declaration/src/**/*.ts",
     "./packages/babel-helper-transform-fixture-test-runner/src/**/*.ts",
     "./packages/babel-helper-validator-identifier/src/**/*.ts",
@@ -96,6 +97,9 @@
       "@babel/helper-simple-access": [
         "./packages/babel-helper-simple-access/src"
       ],
+      "@babel/helper-skip-transparent-expression-wrappers": [
+        "./packages/babel-helper-skip-transparent-expression-wrappers/src"
+      ],
       "@babel/helper-split-export-declaration": [
         "./packages/babel-helper-split-export-declaration/src"
       ],