diff --git a/framework/core/js/src/common/utils/string.js b/framework/core/js/src/common/utils/string.ts
similarity index 75%
rename from framework/core/js/src/common/utils/string.js
rename to framework/core/js/src/common/utils/string.ts
index 73623d8a2..be7bc92d1 100644
--- a/framework/core/js/src/common/utils/string.js
+++ b/framework/core/js/src/common/utils/string.ts
@@ -1,12 +1,7 @@
 /**
  * Truncate a string to the given length, appending ellipses if necessary.
- *
- * @param {String} string
- * @param {Number} length
- * @param {Number} [start=0]
- * @return {String}
  */
-export function truncate(string, length, start = 0) {
+export function truncate(string: string, length: number, start: number = 0): string {
   return (start > 0 ? '...' : '') + string.substring(start, start + length) + (string.length > start + length ? '...' : '');
 }
 
@@ -17,11 +12,8 @@ export function truncate(string, length, start = 0) {
  * NOTE: This method does not use the comparably sophisticated transliteration
  * mechanism that is employed in the backend. Therefore, it should only be used
  * to *suggest* slugs that can be overridden by the user.
- *
- * @param {String} string
- * @return {String}
  */
-export function slug(string) {
+export function slug(string: string): string {
   return string
     .toLowerCase()
     .replace(/[^a-z0-9]/gi, '-')
@@ -32,11 +24,8 @@ export function slug(string) {
 /**
  * Strip HTML tags and quotes out of the given string, replacing them with
  * meaningful punctuation.
- *
- * @param {String} string
- * @return {String}
  */
-export function getPlainContent(string) {
+export function getPlainContent(string: string): string {
   const html = string.replace(/(<\/p>|<br>)/g, '$1 &nbsp;').replace(/<img\b[^>]*>/gi, ' ');
 
   const dom = $('<div/>').html(html);
@@ -55,10 +44,7 @@ getPlainContent.removeSelectors = ['blockquote', 'script'];
 
 /**
  * Make a string's first character uppercase.
- *
- * @param {String} string
- * @return {String}
  */
-export function ucfirst(string) {
+export function ucfirst(string: string): string {
   return string.substr(0, 1).toUpperCase() + string.substr(1);
 }