functional conditional

conditional.js

export const matched = param => ({
  on: () => matched(param),
  otherwise: () => param,
});

export const matchRedirect = param => ({
  on: (pred, fn) => (pred(param) ? matched(fn(param)) : matchRedirect(param)),
  otherwise: fn => fn(param),
});

export const emailRedirect = () => {
  if (has.destination) {
    return matchRedirect(has.destination)
      .on(param => param === 'webviewEndYear', () => resultParams('openbrowser?url=webviewEndYear'))
      .otherwise(param => resultParams(param));
  }
  return resultParams('dashboard');
}