Function scaleKey

docs/tests/v2/es6/js/sanddance.js:110969–110982

(_)

};

function scaleKey(_) {
  var t = _.type,
      d = '',
      n; // backwards compatibility pre Vega 5.

  if (t === _vegaScale.Sequential) return _vegaScale.Sequential + '-' + _vegaScale.Linear;

  if (isContinuousColor(_)) {
    n = _.rawDomain ? _.rawDomain.length : _.domain ? _.domain.length + +(_.domainMid != null) : 0;
    d = n === 2 ? _vegaScale.Sequential + '-' : n === 3 ? _vegaScale.Diverging + '-' : '';
  }

  return (d + t || _vegaScale.Linear).toLowerCase();
}

function isContinuousColor(_) {
  const t = _.type;