diff --git a/src/libs/actions/Modal.js b/src/libs/actions/Modal.ts
similarity index 74%
rename from src/libs/actions/Modal.js
rename to src/libs/actions/Modal.ts
index ea3bfc351593..ff09731f59a7 100644
--- a/src/libs/actions/Modal.js
+++ b/src/libs/actions/Modal.ts
@@ -1,25 +1,20 @@
 import Onyx from 'react-native-onyx';
 import ONYXKEYS from '../../ONYXKEYS';
 
-let closeModal;
-let onModalClose;
+let closeModal: (isNavigating: boolean) => void;
+let onModalClose: null | (() => void);
 
 /**
  * Allows other parts of the app to call modal close function
- *
- * @param {Function} [onClose]
  */
-function setCloseModal(onClose) {
+function setCloseModal(onClose: () => void) {
     closeModal = onClose;
 }
 
 /**
  * Close modal in other parts of the app
- *
- * @param {Function} [onModalCloseCallback]
- * @param {Boolean} isNavigating
  */
-function close(onModalCloseCallback, isNavigating = true) {
+function close(onModalCloseCallback: () => void, isNavigating = true) {
     if (!closeModal) {
         // If modal is already closed, no need to wait for modal close. So immediately call callback.
         if (onModalCloseCallback) {
@@ -42,20 +37,16 @@ function onModalDidClose() {
 
 /**
  * Allows other parts of the app to know when a modal has been opened or closed
- *
- * @param {Boolean} isVisible
  */
-function setModalVisibility(isVisible) {
+function setModalVisibility(isVisible: boolean) {
     Onyx.merge(ONYXKEYS.MODAL, {isVisible});
 }
 
 /**
  * Allows other parts of app to know that an alert modal is about to open.
  * This will trigger as soon as a modal is opened but not yet visible while animation is running.
- *
- * @param {Boolean} isVisible
  */
-function willAlertModalBecomeVisible(isVisible) {
+function willAlertModalBecomeVisible(isVisible: boolean) {
     Onyx.merge(ONYXKEYS.MODAL, {willAlertModalBecomeVisible: isVisible});
 }