How to use

describeOptKeys

function

in

lodash

function keys({req = [], opt = []}) {
  return {
    req,
    opt,
    conform: value => (
      _.every(req, key => isValidRequiredKey(value, key)) &&
        _.every(opt, key => isValidOptionalKey(value, key))) ? value : invalidString,
    unform: _.identity,
    gen: () => tcg.null.then(() => tcg.object(createGeneratorObject(createKeys(req, opt)))),
    describe: () => [keys.name, ...describeReqKeys(req), ...describeOptKeys(opt)],
    explain: function*(value, {via}) {
      yield* explainInvalid(value, req, via, true);
      yield* explainInvalid(value, opt, via, false);
    }
  };
}