lib/get-transitive-data.js
function getRouteIndexFromPatternId (pattern: string | number): number {
    const pat = transitiveNetwork.patterns.find(p => p.pattern_id === String(pattern))
    if (!pat) return -1
    return transitiveNetwork.routes.findIndex(r => r.route_id === pat.route_id)
  }
function getRouteIndexFromPatternId (pattern: string | number): number {
    const pat = transitiveNetwork.patterns.find(p => p.pattern_id === String(pattern))
    if (!pat) return -1
    return transitiveNetwork.routes.findIndex(r => r.route_id === pat.route_id)
  }
function to convert pattern ID to route ID