text: import { isArray } from 'vega-util';
  export const DEFAULT_SORT_OP = 'mean';
  const SORT_BY_CHANNEL_INDEX = {
      x: 1,
      y: 1,
      color: 1,
      fill: 1,
      stroke: 1,
      strokeWidth: 1,
      size: 1,
      shape: 1,
      fillOpacity: 1,
      strokeOpacity: 1,
      opacity: 1,
      text: 1
  };
  export function isSortByChannel(c) {
      return !!SORT_BY_CHANNEL_INDEX[c];
  }
  export function isSortByEncoding(sort) {
      return !!sort && !!sort['encoding'];
  }
  export function isSortField(sort) {
      return !!sort && (sort['op'] === 'count' || !!sort['field']);
  }
  export function isSortArray(sort) {
      return !!sort && isArray(sort);
  }
  //# sourceMappingURL=sort.js.map