njt-api

A Javascript (Typescript) API for accessing trip information for NJTransit trains

API Usage

After installing this package with yarn add njt-api (or npm install njt-api --save), you can either import the default import, or import the Stations and Trips sub-sections of the API:

import * as NJTApi from 'njt-api'
// or
import { Trips, Stations } from 'njt-api'

When using in a React Native project, you'll need to import slightly differently:

import * as NJTApi from 'njt-api/native'

This is because underlying packages within the library (cheerio, namely) do not work within React Native, and need to be swapped out with compatible packages, depending on the context. Other than the change in import path though, the remainder of the API is the same.

Each sub-section has its usages documented below, with signatures/types described using Typescript.

Stations

import { Stations } from 'njt-api'

Function	Returns	Notes
Stations.getStationNames()	string[]
Stations.getStations()	{ [stationName: string]: StationInfo }
Stations.getStationInfo(stationName: string)	StationInfo	Will throw an Error if given an unrecognized/invalid station name
Stations.getStationScheduleIds()	string[]	These are the scheduleIds needed for the Schedule API

where StationInfo is defined as:

type StationInfo = {
  name: string
  lat: number
  long: number
  departureVisionEnabled: boolean
  departureVisionId: string
}

Schedule

import { Schedule } from 'njt-api'

The Schedule API lists out all of the trips between two stations on a given date. When possible, use this API instead of the Trips API. There is only one function here:

async function getScheduleForDay(
  originStation: string,
  destStation: string,
  when?: Date | string
): Promise<Schedule>

where Schedule is defined as:

type Schedule = {
  results: ScheduleResult[]
}

and ScheduleResult is:

type ScheduleResult = {
  origin: {
    time: string
    trainLine: string
    trainNumber: number
  }
  transfer: null | {
    arrivalTime: string
    station: string
    departureTime: string
    trainLine: string
    trainNumber: number
    waitTime: number
  }
  arrivalTime: string
  travelTime: number
}

Eventually there may be additional fields added to the Schedule type, but for now it's just the trips throughout the day. It's important to note that the originStation and destStation must be stations for which there are schedule ids (which are present in the data/schedule-ids.json file). The Promise will fail if unknown stations are passed, or if an invalidly-formatted time string is passed.

Trips

import { Trips } from 'njt-api'

As of right now, there is only one function in the Trip sub-section of the API:

Trips.getTripOptions(fromStation: string, toStation: string, when?: Date | string): Promise<Trip[]>

where Trip is defined as:

type Trip = {
  phases: TripPhase[]
  transferDurations: number[] // For trips with multiple phases, the amount (in minutes) of each transfer wait
}

and TripPhase is defined as:

type TripPhase = {
  departure: {
    from: string
    at: string
  }
  board: {
    trainNumber: string
    towards: string
  }
  arrival: {
    destination: string
    at: string
  }
  duration: number // Duration of the trip phase (in minutes)
}

The getTripOptions function returns 3 trip options, each of which can have multiple 'phases'. For example, traveling between station X and Y might have options 1 and 2 which are direct, but option 3 which has a transfer at station Z. Direct trips only have a single trip phase, but trips with transfers will have a phase for each leg of the trip.

Notes:

• The getTripOptions Promise will fail if given an unrecognized/invalid station name for either the fromStation or toStation
• The third parameter (when) is optional, and will default to the current date and time. If an invalid Date is passed, or an invalidly formatted date string (or any other non-Date, non-string object) the getTripOptions Promise will fail.
• This Promise typically takes a few seconds (yeah, I know) since it's making requests to the NJTransit website and parsing responses. I'd like for that to not be the case, but it's likely the best I can do.

Important Notes

I obviously do not own the rights to New Jersey Transit, NJTransit, NJT, or any other potentially copyrighted terms used in this document or API.