Class ChainHead

client

options

prefix

• get prefix(): string

• The prefix of the group

  Returns string

emit

• emit(event, ...args): boolean

• Parameters

  • event: ChainHeadEvent
  • Rest...args: any[]

  Returns boolean

off

• off(event, handler?): this

• Parameters

  • event: ChainHeadEvent
  • Optionalhandler: HandlerFn

  Returns this

on

• on(event, handler): Unsub

• Parameters

  • event: ChainHeadEvent
  • handler: HandlerFn

  Returns Unsub

once

• once(event, handler): Unsub

• Parameters

  • event: ChainHeadEvent
  • handler: HandlerFn

  Returns Unsub

send

• send<T>(method, ...params): Promise<T>

• Send a json-rpc request, note the method should not contain the prefix and version parts.

  Type Parameters

  • T = any

  Parameters

  • method: string
  • Rest...params: any[]

  Returns Promise<T>

  Example

  const client = await JsonRpcClient.new('wss://rpc.polkadot.io');
  const achieve = new JsonRpcGroup(client, { prefix: 'archive', supportedVersions: ['unstable'] });
  
  const finalizedHeight = await achieve.send<number>('finalizedHeight'); // sending archive_unstable_finalizedHeight
  console.log(finalizedHeight);
  Copy

supported

• supported(): Promise<boolean>

• Check if the group is supported by the connected JSON-RPC server.

  Returns Promise<boolean>

version

• version(): Promise<JsonRpcGroupVersion>

• Detect & return the version of the group. This will be used to construct the json-rpc method name.

  Returns Promise<JsonRpcGroupVersion>