code: function sortPropLabel(propLabel) {
    return _.partition(_.flatten(arguments), function(arg) {
      // catch prop JSON, or *Dist string for edge
      return _.isPlainObject(arg) || _.startsWith(arg, '*')
    })
  }
docs: Sort the array of prop-Label pair given with (propLabel), or ([propLabel]), where each is optional, into [[prop], [Label]]. Prop can also be a Dist string (startsWith '*') for edge.
  @private
  @param  {Array} propLabel Together in an array. Either is optional.
  @return {Array}           Of sorted [[prop], [Label]], either can be empty.
   /* istanbul ignore next