Fetch() post request to Etsy API using URLSearchParams() package from npm

Hi, I am trying to upload images to a 3d party API (Etsy) using this code and getting the error in back-end module:
_urlSearchParamsPolyfill.default is not a constructor

Any Idea?

import URLSearchParams from 'url-search-params-polyfill'; // installed from npm
export async function CATS2() {

    var etsyOauth_consumer_key = await getSecret('etsyOauth_consumer_key');
    var etsyListingPostUrlV2 = await getSecret('etsyListingPostUrlV2');
    var etsyListingPutUrlV2 = await getSecret('etsyListingPutUrlV2');
    var etsyListingGetUrl = await getSecret('etsyListingGetUrl');
    var etsyOauth_token = await getSecret('etsyOauth_token');
    var etsyOauth_signature = await getSecret('etsyOauth_signature');
    var etsyOauth_nonce = await getSecret('etsyOauth_nonce');
    var etsyOauth_timestamp = await getSecret('etsyOauth_timestamp');

    var fetchUrlPutImages = etsyListingPutUrlV2 + '/' + '1097251918' + '/' + 'images' + '?' + 'oauth_consumer_key=' + etsyOauth_consumer_key + '&' + 'oauth_signature_method=PLAINTEXT' + '&' +
        'oauth_token=' + etsyOauth_token + '&' + 'oauth_signature=' + etsyOauth_signature + '&' + 'oauth_nonce=' + etsyOauth_nonce + '&' +
        'oauth_timestamp=' + etsyOauth_timestamp

    var urlencoded = new URLSearchParams();
    urlencoded.append("image", "aHR0cHM6Ly9yZXMuY2xvdWRpbmFyeS5jb20vcHJpbnRqdW1wZXIvaW1hZ2UvdXBsb2FkL2Vfc2hhZG93OjE1MCxjb19ibGFjayx4XzEyLHlfNyxsX3hsbXpxbmFhaHpjenR1bG9kbnQzLnBuZyxjX2ZpbGwsd18xNDQsaF8xNDQveV8tNDAwLHhfMCxmbF9sYXllcl9hcHBseS9mbF9hdHRhY2htZW50L3RvMXV5eTRjNGpweG9tZ2VscXVzLmpwZw");

        return fetch(fetchUrlPutImages, {
                'method': 'post',
                "headers": [],
                'body': urlencoded
            }

        )
        .then(response => response.text())

}