Topics

Prefer the typed factories (getDoubleTopic, getStringTopic, …). createTopic(name, typeInfo, defaultValue?) remains for cases where the type is not known until runtime.

Topic factories

getDoubleTopic(name: string, defaultValue?: number)
getStringTopic(name: string, defaultValue?: string)
getBooleanTopic(name: string, defaultValue?: boolean)
getIntegerTopic(name: string, defaultValue?: number)
getFloatTopic(name: string, defaultValue?: number)
getBooleanArrayTopic(name: string, defaultValue?: boolean[])
getDoubleArrayTopic(name: string, defaultValue?: number[])
getIntegerArrayTopic(name: string, defaultValue?: number[])
getFloatArrayTopic(name: string, defaultValue?: number[])
getStringArrayTopic(name: string, defaultValue?: string[])
getRawTopic(name: string, defaultValue?: Uint8Array)
getJsonTopic<T extends object>(name: string, defaultValue?: T, options?: { validator?: ZodSchema<T> })

Once a topic has been created, subscribe with:

subscribe(
  callback: (value: T | null, params: AnnounceMessageParams) => void,
  options?: SubscribeOptions
)

and/or publish with:

await publish(properties: TopicProperties = {})

Subscribe example

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

const ntcore = NetworkTables.getInstanceByTeam(973);

const gyroTopic = ntcore.getDoubleTopic('/MyTable/Gyro');

gyroTopic.subscribe((value) => {
  console.log(`Got Gyro Value: ${value}`);
});

gyroTopic.subscribe((value, params) => {
  console.log(`Got Gyro Value: ${value} at from topic id ${params.id}`);
});

Publish example

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

const ntcore = NetworkTables.getInstanceByTeam(973);

const autoModeTopic = ntcore.getStringTopic('/MyTable/AutoMode', 'No Auto');

await autoModeTopic.publish();

autoModeTopic.setValue('25 Ball Auto and Climb');

Related

• Prefix topics for wildcard subscriptions
• Protobuf and struct for binary types
• API reference for the full topic API

Known limitations

• "Raw" and other binary types (RPC, msgpack, protobuf) use Uint8Array; the library does not use ArrayBuffer directly for topic values.