ntcore-ts-client

A TypeScript library for communication over WPILib's NetworkTables 4.0 protocol.

Features

• NodeJS and DOM support
• Togglable auto-reconnect
• Callbacks for new data on subscriptions
• Callbacks for connection listeners
• Retrying for messages queued during a connection loss
• On-the-fly server switching with resubscribing and republishing
• Generic types for Topics
• Client-side data validation using Zod
• Server-matching timestamping using RTT calculation

Documentation

TypeDocs are available at https://ntcore.chrislawson.dev

Quick Start

This section will help get you started with sending and receiving data over NetworkTables

Installation

npm install --save ntcore-ts-client

Connecting to the NetworkTables Server

The NetworkTables class is instance-based, but allows for connections to multiple teams/URIs.

Importing NetworkTables

Use this at the top of your file:

import { NetworkTables } from 'ntcore-ts-client';

With Team Number

Use this function:

NetworkTables.getInstanceByTeam(team: number, port = 5810)

This creates the instance using the team number. Connects to roborio-<team>-frc.local

With URI

Use this function:

NetworkTables.getInstanceByURI(uri: string, port?)

This creates the instance using a custom URI, i.e. 127.0.0.1, localhost, google.com, etc.

Publishing and Subscribing to a Topic

To use a Topic, it must be created through the NetworkTables client using the function:

createTopic<T extends NetworkTablesTypes>(name: string, typeInfo: NetworkTablesTypeInfo, defaultValue?: T)

The valid NetworkTablesTypes are string | number | boolean | string[] | ArrayBuffer | boolean[] | number[]

The valid NetworkTablesTypeInfos are:

• NetworkTablesTypeInfos.kBoolean
• NetworkTablesTypeInfos.kDouble
• NetworkTablesTypeInfos.kInteger
• NetworkTablesTypeInfos.kString
• NetworkTablesTypeInfos.kArrayBuffer
• NetworkTablesTypeInfos.kBooleanArray
• NetworkTablesTypeInfos.kDoubleArray
• NetworkTablesTypeInfos.kIntegerArray
• NetworkTablesTypeInfos.kStringArray

Once a topic has been created, it can be used as a subscriber:

subscribe(
  callback: (_: T | null) => void,
  immediateNotify = false,
  options: SubscribeOptions = {},
  id?: number,
  save = true
)

and/or a publisher:

await publish(properties: TopicProperties = {}, id?: number)

For example, here's a subscription for a Gyro:

import { NetworkTables, NetworkTablesTypeInfos } from 'ntcore-ts-client';

// Get or create the NT client instance
const ntcore = NetworkTables.getInstanceByTeam(973);

// Create the gyro topic
const gyroTopic = ntcore.createTopic<number>('/MyTable/Gyro', NetworkTablesTypeInfos.kDouble);

// Subscribe and immediately call the callback with the current value
gyroTopic.subscribe((value) => {
  console.log(`Got Gyro Value: ${value}`);
}, true);

Or a publisher for an auto mode:

import { NetworkTables, NetworkTablesTypeInfos } from 'ntcore-ts-client';

// Get or create the NT client instance
const ntcore = NetworkTables.getInstanceByTeam(973);

// Create the autoMode topic w/ a default return value of 'No Auto'
const autoModeTopic = ntcore.createTopic<string>('/MyTable/autoMode', NetworkTablesTypeInfos.kString, 'No Auto');

// Make us the publisher
await autoModeTopic.publish();

// Set a new value, this will error if we aren't the publisher!
autoModeTopic.setValue('25 Ball Auto and Climb');

More info

The API for Topics is much more exhaustive than this quick example. Feel free to view the docs at https://ntcore.chrislawson.dev.

Known Limitations

• "Raw" type only supports ArrayBuffer

Contributing

Contributions are welcome and encouraged! If you encounter a bug, please open an issue and provide as much information as possible. If you'd like to open a PR, I'll be more than happy to review it as soon as I can!