diff --git a/src/utils/UrlUtils.js b/src/utils/UrlUtils.ts
similarity index 88%
rename from src/utils/UrlUtils.js
rename to src/utils/UrlUtils.ts
index 7b207c128e..6f441ff98e 100644
--- a/src/utils/UrlUtils.js
+++ b/src/utils/UrlUtils.ts
@@ -1,5 +1,5 @@
 /*
-Copyright 2019 The Matrix.org Foundation C.I.C.
+Copyright 2019, 2021 The Matrix.org Foundation C.I.C.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -22,7 +22,7 @@ import url from "url";
  * @param {string} u The url to be abbreviated
  * @returns {string} The abbreviated url
  */
-export function abbreviateUrl(u) {
+export function abbreviateUrl(u: string): string {
     if (!u) return '';
 
     const parsedUrl = url.parse(u);
@@ -37,7 +37,7 @@ export function abbreviateUrl(u) {
     return u;
 }
 
-export function unabbreviateUrl(u) {
+export function unabbreviateUrl(u: string): string {
     if (!u) return '';
 
     let longUrl = u;
diff --git a/src/utils/humanize.js b/src/utils/humanize.ts
similarity index 83%
rename from src/utils/humanize.js
rename to src/utils/humanize.ts
index 6e6f17f8f4..55bdbf760b 100644
--- a/src/utils/humanize.js
+++ b/src/utils/humanize.ts
@@ -1,5 +1,5 @@
 /*
-Copyright 2020 The Matrix.org Foundation C.I.C.
+Copyright 2020, 2021 The Matrix.org Foundation C.I.C.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -14,22 +14,22 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import {_t} from "../languageHandler";
+import { _t } from "../languageHandler";
+
+// These are the constants we use for when to break the text
+const MILLISECONDS_RECENT = 15000;
+const MILLISECONDS_1_MIN = 75000;
+const MINUTES_UNDER_1_HOUR = 45;
+const MINUTES_1_HOUR = 75;
+const HOURS_UNDER_1_DAY = 23;
+const HOURS_1_DAY = 26;
 
 /**
  * Converts a timestamp into human-readable, translated, text.
  * @param {number} timeMillis The time in millis to compare against.
  * @returns {string} The humanized time.
  */
-export function humanizeTime(timeMillis) {
-    // These are the constants we use for when to break the text
-    const MILLISECONDS_RECENT = 15000;
-    const MILLISECONDS_1_MIN = 75000;
-    const MINUTES_UNDER_1_HOUR = 45;
-    const MINUTES_1_HOUR = 75;
-    const HOURS_UNDER_1_DAY = 23;
-    const HOURS_1_DAY = 26;
-
+export function humanizeTime(timeMillis: number): string {
     const now = (new Date()).getTime();
     let msAgo = now - timeMillis;
     const minutes = Math.abs(Math.ceil(msAgo / 60000));