How to implement AES ECB PKCS5Padding 128-bit data block encryption in pre-request script?

I need to use AES ECB encryption to generate a parameter in my URL, but the CryptoJS module can not get the right result. Here is my code:

var plainText = "abcdefg1234567890abc"
console.log(plainText)
var key = "abcdefmiddleware";
var result = CryptoJS.AES.encrypt(
      CryptoJS.enc.Utf8.parse(plainText),
      key,
         {
          keySize: 128,
          mode: CryptoJS.mode.ECB,
          padding: CryptoJS.pad.Pkcs7
        }
);
var b64 = result.ciphertext.toString(CryptoJS.enc.Base64);
console.log(b64)
pm.collectionVariables.set("signature",encodeURIComponent(b64));

The output changes every time I run the request, and the correct result should be
“W30nAtv/zP0+oOYMbN1fP7cpAmVWG3Zr63As6vBqA3c=”

Does anyone know how to solve this? Thanks.