Google recaptcha wrapper for grecaptcha.execute() with version 2 fallback.

recaptcha_fallback.js

function execute(action, callback) {
  // create real promise, because execute method does not return the real one
  // (missing documentation what actually returns)
  const promise = new Promise((resolve, reject) => {
    grecaptcha.ready(() =>
      grecaptcha.execute(key, { action }).then(token => {
        resolve(token);
      },
      reject)
    );
  })
    .then(token => callback(token, false)) // v3 token
    .catch(err => {
      const transformedErr = errorService.transformError(err); process error from backend

      if (transformedErr.type === 'reCaptcha') { // v3 was unsuccessful, fallback to v2 to give user chance to prove his humanity
        return renderV2().then(token => callback(token, true));
      }
      // else errors rethrow to continue to other catches
      throw err;
    });
  return promise;
}

function renderV2() {
  const promise = new Promise((resolve, reject) => {
    grecaptcha.ready(() => {
      grecaptcha.render('recaptcha-container', {
        sitekey: keyV2,
        callback: resolve,
        'expired-callback': () => {
          grecaptcha.reset('recaptcha-container');
        },
        'error-callback': reject,
      });
    });
  });
  return promise;

////////////////////////////////////////////////////////////////////////////////////////
// Example of usage ////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////

function checkName(name) {
  return execute('check', (reCapToken, V2) =>
      axios
        .get('/check', {
          params: {
            login,
            reCapToken,
            reCaptV2: V2,
          },
        })
    );
}