Updates

Getting updates is one of the most important parts of a Telegram application. Updates contain notifications about data changes. You can use middleware to get them, as in the example below:

// ctx is UpdateContext | ApiResponse
airgram.use((ctx, next) => {
  // Checks if this operation is UpdateContext
  if ('update' in ctx) {
    console.log(`[all updates][${ctx._}]`, JSON.stringify(ctx.update))
  }
  return next()
})

In common case, middleware's context can be represented by UpdateContext type or ApiResponse type, so you need to check that this is an update.

Updates context implements the following interface:

interface UpdateContext {
  _: string
  update: Record<string, any>
  airgram: Airgram
  setState: Function
  getState: Function
}

If you need to subscribe to certain updates, we recommend using the on method because it gives you full type checking support.

The first argument specifies the type of updates you want to receive. The second one sets a callback function, which will be called each time for corresponding update type.

interface UpdateContext {
  _: 'updateNewMessage' // recognized
  update: UpdateNewMessage // recognized
  airgram: Airgram
  setState: Function
  getState: Function
}

airgram.on('updateNewMessage', async ({ update }) => {
  // `update` resolved as `UpdateNewMessage`
  const { message } = update
  console.log('[new message]', message)
})

If you need to fire some update, use emit method on Airgram instance:

airgram.on('foo', (ctx, next) => {
  console.log(ctx.update.bar) // output: baz
  return next()
})

airgram.emit({
  _: 'foo',
  bar: 'baz'
})