feat(ts) migrate modules\util\RandomUtil to TS

modules/util/RandomUtil.js → modules/util/RandomUtil.ts

  * @param max the maximum value for the generated number
  * @returns random int number
  */
-function randomInt(min, max) {
+export function randomInt(min: number, max: number): number {
     return Math.floor(Math.random() * (max - min + 1)) + min;
 }
 
  * @param {Array|string} arr source
  * @returns array element or string character
  */
-function randomElement(arr) {
+export function randomElement<T>(arr: T[] | string): T | string {
     return arr[randomInt(0, arr.length - 1)];
 }
 
  * @param {number} length expected string length
  * @returns {string} random string of specified length
  */
-function randomAlphanumStr(length) {
+export function randomAlphanumStr(length: number): string {
     let result = '';
 
     for (let i = 0; i < length; i += 1) {
      * Returns a random hex digit.
      * @returns {*}
      */
-    randomHexDigit() {
-        return randomElement(HEX_DIGITS);
+    randomHexDigit(): string {
+        return randomElement(HEX_DIGITS) as string;
     },
 
     /**
      * Returns a random string of hex digits with length 'len'.
      * @param len the length.
      */
-    randomHexString(len) {
+    randomHexString(len: number): string {
         let ret = '';
 
         while (len--) { // eslint-disable-line no-param-reassign
     randomInt
 };
 
-module.exports = RandomUtil;
+export default RandomUtil;