Watch DEX Order Cancellations

Watches OrderCancelled events on the DEX.

Usage

import { client } from './viem.config'
 
const watcher = client.dex.watchOrderCancelled()
 
watcher.onLogs((logs) => {
  for (const log of logs) console.log(log.args)
{  orderId: 123n,}
})
 
// Later, tear down the watcher.
watcher.off()

import { Account, Client } from 'viem/tempo'
 
export const client = Client.create({
  account: Account.fromSecp256k1('0x...'),
})

Also callable standalone: Actions.dex.watchOrderCancelled(client, options), with Actions imported from 'viem/tempo'.

Recipes

Detect Cancellations You Did Not Initiate

Filter by your tracked order IDs to keep an open-orders store accurate: anyone can clear stale orders with dex.cancelStale, so cancellations can happen without your involvement.

import { client } from './viem.config'
 
const openOrderIds = [123n, 456n]
 
const watcher = client.dex.watchOrderCancelled({
  args: { orderId: openOrderIds },
})
 
watcher.onLogs((logs) => {
  for (const log of logs) console.log('Remove from store:', log.args.orderId)
Remove from store: 123n
})

import { Account, Client } from 'viem/tempo'
 
export const client = Client.create({
  account: Account.fromSecp256k1('0x...'),
})

Return Value

Returns a watcher handle. Watching starts when the first listener (or async iterator) attaches, and stops when off is called.

type ReturnType = {
  /** Registers a log listener. Starts the watcher on first registration. Returns an unregister function. */
  onLogs: (fn: (logs: readonly Log[]) => void) => () => void
  /** Registers an error listener. Returns an unregister function. */
  onError: (fn: (error: Error) => void) => () => void
  /** Tears down the watcher: removes listeners, ends iterators, stops the poll or subscription. */
  off: () => void
  /** Async-iterates emitted log batches (latest-only stream). */
  [Symbol.asyncIterator]: () => AsyncIterableIterator<{ logs: readonly Log[] }>
}

Each log is decoded, with the event arguments on args:

type Log = {
  /** Decoded `OrderCancelled` event arguments. */
  args: {
    /** Cancelled order ID. */
    orderId: bigint
  }
  /** Name of the emitted event. */
  eventName: 'OrderCancelled'
  // ...standard log fields (address, blockHash, blockNumber, logIndex, transactionHash, ...)
}

Parameters

args

• Type: object

type Args = {
  /** Filter by order ID. */
  orderId?: bigint | readonly bigint[] | null
}

Indexed argument values to filter logs by.

batch

• Type: boolean
• Default: true

Whether to batch the logs found within a poll interval into a single emission. When false, each log is emitted on its own.

fromBlock

• Type: bigint

Block number from which to start watching for logs.

poll

• Type: boolean

Whether to poll for new logs instead of using a subscription. Defaults to true when the transport cannot subscribe or fromBlock is provided.

pollingInterval

• Type: number
• Default: client.pollingInterval

Polling frequency (in ms).