fetchTrustBoxData.js

// Transforms an object containing arbitrary keys, and promise values, into a
// promise-wrapped object, with the same keys and the result of resolving each
// promise as values.
const promiseAllObject = (obj) => {
  const keys = Object.keys(obj);
  const values = keys.map((k) => obj[k]);
  return Promise.all(values).then((promises) =>
    promises.reduce((all, promise, idx) => ({ ...all, [keys[idx]]: promise }), {})
  );
}

const fetchTrustBoxData = (
  { businessUnitId, locale, translationFallbacks, theme = 'light', ...opts },
  constructTrustBox
) => {
  const baseDataPromise = ...
  const translationsPromise = ...
  const readyPromise = ...

  return promiseAllObject({
    baseData: baseDataPromise, 
    translations: translationsPromise, 
    ready: readyPromise 
  }).then(({ baseData, translations }) => {
      constructTrustBox({
        translations,
        baseData,
        locale,
      });
      completeLoading(theme, baseData);
    })
    .catch(() => errorFallback())
    .finally(() => removeLoader());
};