index.js
function mapWithIndex (range, index) {
  return {
    start: range.start,
    end: range.end,
    index: index
  }
}
function mapWithIndex (range, index) {
  return {
    start: range.start,
    end: range.end,
    index: index
  }
}
function mapWithIndex ( range , index ) { return { start : range . start , end : range . end , index : index } }
Map function to add index value to ranges.
@private
Map function to add index value to ranges .