Once

function in meocord/decorator Since 4.1.0

Once<E extends keyof ClientEvents>(
  event: E,
): <F extends (...args: ClientEvents[E]) => unknown>(
  target: object,
  propertyKey: string,
  _descriptor: TypedPropertyDescriptor<F>,
) => void

Handles a discord.js client event the first time it is emitted only, on a controller or a service.

Use it for one-off work on an event, such as warming a cache once the client is ready. For every emission, use On; for work at startup and shutdown, a service's onReady and onShutdown hooks.

Where it runs

The handler — with the guards, interceptors and filters that apply to events: the app's global ones, its class's and its own

Parameters

Name	Type	Description
`event`	`E`	The client event to handle, such as `'clientReady'`.

Returns

Returns a method decorator.

<F extends (...args: ClientEvents[E]) => unknown>(
  target: object,
  propertyKey: string,
  _descriptor: TypedPropertyDescriptor<F>,
) => void

Examples

TypeScript

@Service()
export class CacheWarmer {
  @Once('clientReady')
  async warm(client: Client<true>) {
    await client.guilds.fetch()
  }
}