Encode string Base64

[lichade2016]

Hi, I am using the same code but an error occurs.

My code is this:

//page code

import {myFunction} from 'backend/encodeString.jsw';

$w.onReady(async function () {
 let string = '50033027299715739fa316d303aa-2ae2c6f3-33b0afdd';
 const newStr = myFunction(string)
    console.log(newStr)
});

//backend encodeString.jsw 
import encode from "nodejs-base64-encode";

export function myFunction(string) {
 var base64File = encode.encode(string, 'base64');
 return base64File;
}

Is there something I did wrong?