Function domain

docs/tests/v2/es6/js/sanddance.js:130263–130266

(name, group)

}

function domain(name, group) {
  const s = getScale(name, (group || this).context);
  return s ? s.domain() : [];
}

function bandwidth(name, group) {
  const s = getScale(name, (group || this).context);