var gcVerifier = require("gamecenter-identity-verifier")
var identity = {"signature":"ZGc0qwJwgBw6XTnFehOC72k/LVJp4VR7CepPOhYHcS3OxqpvVlBFiKsl/HowE6hcNP0tn/uC/pasHQof3W+vjTXjoCQZk8n+LC0U+32FkaLi0rzC9vZ6Hkr2GQVGFhkPecUbG+YEiFVvj3XAqvg+/6xcSTF0FqVQ/udEpzofHofNxk6kPmZIzhEYOVudslRloyDO4DaIFGx1XCLlZco8c1NEVVZxal1xADk5RIjgTY123Lj59CwJa1ma8tXQQ/QWqcDIgjGqggYuhBhtNlJj1SX4hl7Lpvya/JwdjNV69dxkSNaQzogQX+EmN2NMtCw67X3MdPQ2y1pXoIm8jIwYJA==","publicKeyUrl":"https://static.gc.apple.com/public-key/gc-prod-4.cer","timestamp":"1556010428749","playerId":"G:1323375045","salt":"Zs5Blg==", "bundleId":"net.tests.numbako"}

var verifier = new Promise(function(resolve, reject) {
    gcVerifier.verify(identity, function (err, token) {
      if (!err) {
        resolve(token);
      }
      else {
        reject();
      }
    });
});

async function waitVerification() {
    const res = await verifier.then(function(data) {
        return data;
    }).catch(function() {return "21321"});
    return res;
}

const verificationResult = await waitVerification();
console.log(verificationResult);