JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.9-1/crypto-js.js"></script>

JavaScript

var encrypted = CryptoJS.AES.encrypt("TEST_TEXT", '9021D105A446', {
  mode: CryptoJS.mode.ECB,
  padding: CryptoJS.pad.Pkcs7
});
var decrypt = CryptoJS.AES.decrypt(encrypted, '9021D105A446', {
    mode: CryptoJS.mode.ECB,
    padding: CryptoJS.pad.Pkcs7
});
console.log(decrypt.toString(CryptoJS.enc.Utf8));

console.log('ciphertext: ', encrypted.ciphertext.toString());
console.log('encrypted (it is Base64 already): ', encrypted.toString());//already base64
console.log('encrypted decoded from Base64: ', CryptoJS.enc.Base64.parse(encrypted.toString()).toString()); //note that the full crypted string has a whole other part before ciphertext
var decrypt2 = CryptoJS.AES.decrypt(encrypted.ciphertext.toString(), '9021D105A446', {
    mode: CryptoJS.mode.ECB,
    padding: CryptoJS.pad.Pkcs7
});
console.log('ciphertext.toString() not working: ', decrypt2.toString(CryptoJS.enc.Utf8));
var decrypt3 = CryptoJS.AES.decrypt(encrypted.toString(), '9021D105A446', {
    mode: CryptoJS.mode.ECB,
    padding: CryptoJS.pad.Pkcs7
});
console.log('encrypted.toString() working: ', decrypt3.toString(CryptoJS.enc.Utf8));