Topic

Topics (through the Hedera Consensus Service - HCS) are the backbone of Hedera's traffic accounting, at the time of this writing, for more then 85% of the network's traffic. This makes them the hottest services used on the network. Naturally, Venin supports them with more features planned for the upcoming future.

Creating a Topic

To create a LiveTopic to which you can post messages, you have a couple of constructor arguments to choose from:

export type TopicFeatures = {
  autoRenewAccountId?: string | AccountId;
  autoRenewPeriod?: number | Long.Long | Duration;
  memo?: string;
  keys?: TopicKeys;
};

type TopicKeys = {
  admin?: Key;
  submit?: Key;
};

None of them are mandatory.

Once set, you create it as you would do with any CreatableEntity and here is an example:

Live Editor

const { session } = await ApiSession.default(); const liveTopic = await session.create(new Topic()); log(`Topic is available at ${liveTopic.id}`);

const { session } = await ApiSession.default();
const liveTopic = await session.create(new Topic());

log(`Topic is available at ${liveTopic.id}`);

Loading...

Retrieving a Topic

Is not currently possible but will be once issue #60 gets resolved.

LiveTopic operations

Currently, LiveTopics support sending messages via their LiveTopic.submitMessage(message) method. message can be either a string or a Uint8Array. Subscribing to messages will be possible following the resolving of issue #47.

Deleting a Topic

To delete a LiveTopic just call its LiveTopic.deleteEntity(). This will succeeds if the account owning the wallet configured in the ApiSession has the rights to do so.

note

Once deleted, certain operations such as the submitMessage one and, in general, all network-related actions, are no longer available.

Updating a Topic

LiveTopics can be updated like any other LiveEntity: by calling its LiveTopic.updateEntity(TopicFeatures) method.