HcsTopicService API Reference

This document provides a detailed API reference for the HcsTopicService class — a service for managing Hedera Consensus Service (HCS) topics, including creating, updating, deleting topics, and retrieving topic info.

Сonstructor

constructor

constructor(client: Client, cache?: CacheConfig | Cache | HcsCacheService)

Creates a new instance of HcsTopicService.

Parameters

  • client (required): Hedera SDK client instance used for HCS operations.

  • cache (optional): Cache configuration, cache instance, or an existing HcsCacheService.

Methods

createTopic

async createTopic(props?: CreateTopicProps): Promise<string>

Creates a new HCS topic.

Parameters

  • props (optional): Properties to configure topic creation.

CreateTopicProps fields:

  • topicMemo (optional, string): Description or memo for the topic.

  • adminKeySigner (optional, Signer): Signer for a private key that must sign any transaction updating the topic (admin rights).

  • submitKey (optional, PrivateKey | PublicKey): Key permitted to submit messages.

  • autoRenewPeriod (optional, Duration | Long | number): Topic auto-renew period in seconds.

  • autoRenewAccountId (optional, AccountId | string): Account ID to be charged for auto-renewal fees.

  • autoRenewAccountKeySigner (optional, Signer): Signer for the auto-renewal account (required if autoRenewAccountId is provided).

  • waitForChangesVisibility (optional, boolean): If true, waits until the topic visibility is confirmed in the mirror node.

  • waitForChangesVisibilityTimeoutMs (optional, number): Timeout in milliseconds to wait for changes visibility.

Returns

  • A promise resolving to the created topic ID as a string.

Throws

  • Error if autoRenewAccountId is provided without autoRenewAccountKey.

  • Error if the topic creation transaction fails.

updateTopic

async updateTopic(props: UpdateTopicProps): Promise<void>

Updates an existing HCS topic.

Parameters

  • props (required): Properties for updating the topic.

UpdateTopicProps fields:

  • topicId (required, string): The ID of the topic to update.

  • currentAdminKeySigner (required, Signer): Signer for the current admin key required to sign the update transaction.

  • topicMemo (optional, string): New memo for the topic (set empty string to clear).

  • submitKey (optional, PrivateKey): New submit key.

  • adminKeySigner (optional, Signer): Signer for a new admin key that must sign any transaction updating the topic.

  • autoRenewPeriod (optional, Duration | Long | number): New auto-renewal period (default fallback to 90 days if null).

  • autoRenewAccountId (optional, AccountId | string): New auto-renew account ID.

  • autoRenewAccountKeySigner (optional, Signer): Signer for the auto-renewal account (required if autoRenewAccountId is provided).

  • expirationTime (optional, Timestamp | Date): New expiration time.

  • waitForChangesVisibility (optional, boolean): If true, wait until updated topic info is visible in mirror node.

  • waitForChangesVisibilityTimeoutMs (optional, number): Timeout in milliseconds for visibility wait.

Returns

  • A promise resolving when the topic update completes.

Throws

  • Error if autoRenewAccountId is set without autoRenewAccountKey.

  • Error if the update transaction fails.

deleteTopic

async deleteTopic(props: DeleteTopicProps): Promise<void>

Deletes an HCS topic.

Parameters

  • props (required): Properties for deleting the topic.

DeleteTopicProps fields:

  • topicId (required, string): ID of the topic to delete.

  • adminKeySigner (required, Signer): Signer for the current admin key required to sign the delete transaction.

  • waitForChangesVisibility (optional, boolean): Wait until deletion is confirmed visible in mirror node.

  • waitForChangesVisibilityTimeoutMs (optional, number): Timeout in milliseconds to wait for visibility.

Returns

  • A promise resolving when deletion is complete.

Throws

  • Error if the deletion transaction fails.

getTopicInfo

async getTopicInfo(props: GetTopicInfoProps): Promise<TopicInfo>

Retrieves information about a topic, utilizing cache if available.

Parameters

  • props (required): Properties to specify the topic info to retrieve.

GetTopicInfoProps fields:

  • topicId (required, string): ID of the topic.

Returns

  • A promise resolving to TopicInfo.

Throws

  • Error if topic info retrieval fails.

See Also

HcsTopicService Developer Guide