Find data from one HAFAS endpoint in another one.

Usage no npm install needed!

<script type="module">
  import findHafasDataInAnotherHafas from '';



Find data from one HAFAS endpoint in the data of another HAFAS endpoint.

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Public transport providers in Europe often have data about vehicles run by other companies, but almost always it is outdated or imprecise. Consider these examples: showing TGV 6631 showing TGV 6631 showing IC 2029 showing IC 2029

Let's always get the data about a vehicles from the company that actually run it! Given a leg from an endpoint A, you can use this library to fetch more up-to-date data about it from another endpoint B.

Why linked open transit data? explains more about this idea.


npm install find-hafas-data-in-another-hafas


const createDbHafas = require('db-hafas')
const createVbbHafas = require('vbb-hafas')
const createFindLeg = require('find-hafas-data-in-another-hafas/find-leg')
const createMergeLegs = require('find-hafas-data-in-another-hafas/merge')

// Note that, for legs to be matched reliably, you need a more
// sophisticated normalization function. Use e.g.
// -
// -
const normalizeName = name => str.toLowerCase().replace(/\s/g, '')

const dbHafas = createDbHafas('find-db-hafas-leg-in-another-hafas example')
const dbEndpoint = {
    // The endpoint name should be URL-safe & stable, it will be used to compute
    // IDs to be matched against other IDs.
    endpointName: 'db',
    client: dbHafas,
    normalizeStopName: normalizeName,
    normalizeLineName: normalizeName,

const vbbHafas = createVbbHafas('find-db-hafas-leg-in-another-hafas example')
const vbbEndpoint = {
    endpointName: 'vbb',
    client: vbbHafas,
    normalizeStopName: normalizeName,
    normalizeLineName: normalizedName,

const findLegInAnother = createFindLeg(dbEndpoint, vbbEndpoint)
const mergeLegs = createMergeLegs(dbEndpoint, vbbEndpoint)

const potsdamerPlatz = '8011118'
const südkreuz = '8011113'
const res = await dbHafas.journeys(potsdamerPlatz, südkreuz, {
    results: 1, stopovers: true, tickets: false
const [journey] = res.journeys

const dbLeg = journey.legs.find(leg => leg.line) // find non-walking leg
console.log('DB leg', dbLeg)

const vbbLeg = findLegInAnother(dbLeg)
console.log('equivalent VBB leg', leg)

const mergedLeg = mergeLegs(dbLeg, vbbLeg)
console.log('mergedLeg', mergedLeg)


find-hafas-data-in-another-hafas provides the following entry points:

  • find-h…/match-line
  • find-h…/match-stop-or-station
  • find-h…/match-stopover
  • find-h…/find-stop
  • find-h…/find-leg
  • find-h…/find-arr-dep
  • find-h…/merge-leg
  • find-h…/merge-arr-dep

match* functions identify two items (e.g. two journey legs) from different endpoints as equivalent (describing the same thing). Given an item from one endpoint, find* functions find the equivalent in the other endpoint. merge* functions merge two equivalents items found using find*.

All of these functions expect the two endpoints to be specified as follows:

    endpointName: 'oebb', // a *stable* & URL-safe identifier for the endpoint
    client: …, // a hafas-client@5-compatible API client
    // These should return URL-safe, lower-case versions of stop/line names, with
    // as little meaningless/local additions (e.g. "Bus" or "Bhf") as possible.
    // The results will be used to match stops/lines across endpoints!
    normalizeStopName: name => normalizedName,
    normalizeLineName: name => normalizedName,



If you have a question or need support using find-hafas-data-in-another-hafas, please double-check your code and setup first. If you think you have found a bug or want to propose a feature, refer to the issues page.