diff --git a/src/libs/ComposerFocusManager.js b/src/libs/ComposerFocusManager.ts
similarity index 78%
rename from src/libs/ComposerFocusManager.js
rename to src/libs/ComposerFocusManager.ts
index 569e165da962..b66bbe92599e 100644
--- a/src/libs/ComposerFocusManager.js
+++ b/src/libs/ComposerFocusManager.ts
@@ -1,18 +1,20 @@
 let isReadyToFocusPromise = Promise.resolve();
-let resolveIsReadyToFocus;
+let resolveIsReadyToFocus: (value: void | PromiseLike<void>) => void;
 
 function resetReadyToFocus() {
     isReadyToFocusPromise = new Promise((resolve) => {
         resolveIsReadyToFocus = resolve;
     });
 }
+
 function setReadyToFocus() {
     if (!resolveIsReadyToFocus) {
         return;
     }
     resolveIsReadyToFocus();
 }
-function isReadyToFocus() {
+
+function isReadyToFocus(): Promise<void> {
     return isReadyToFocusPromise;
 }
 
diff --git a/src/libs/SuggestionUtils.js b/src/libs/SuggestionUtils.ts
similarity index 70%
rename from src/libs/SuggestionUtils.js
rename to src/libs/SuggestionUtils.ts
index 338f3b455431..96379ce49ef3 100644
--- a/src/libs/SuggestionUtils.js
+++ b/src/libs/SuggestionUtils.ts
@@ -2,21 +2,14 @@ import CONST from '@src/CONST';
 
 /**
  * Trims first character of the string if it is a space
- * @param {String} str
- * @returns {String}
  */
-function trimLeadingSpace(str) {
-    return str.slice(0, 1) === ' ' ? str.slice(1) : str;
+function trimLeadingSpace(str: string): string {
+    return str.startsWith(' ') ? str.slice(1) : str;
 }
-
 /**
  * Checks if space is available to render large suggestion menu
- * @param {Number} listHeight
- * @param {Number} composerHeight
- * @param {Number} totalSuggestions
- * @returns {Boolean}
  */
-function hasEnoughSpaceForLargeSuggestionMenu(listHeight, composerHeight, totalSuggestions) {
+function hasEnoughSpaceForLargeSuggestionMenu(listHeight: number, composerHeight: number, totalSuggestions: number): boolean {
     const maxSuggestions = CONST.AUTO_COMPLETE_SUGGESTER.MAX_AMOUNT_OF_VISIBLE_SUGGESTIONS_IN_CONTAINER;
     const chatFooterHeight = CONST.CHAT_FOOTER_SECONDARY_ROW_HEIGHT + 2 * CONST.CHAT_FOOTER_SECONDARY_ROW_PADDING;
     const availableHeight = listHeight - composerHeight - chatFooterHeight;