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Watch Quote Token Updates

token.watchUpdateQuoteToken

Watches TIP-20 quote token update events for a token. Emits NextQuoteTokenSet when a quote token update is staged, and QuoteTokenUpdate when it is applied.

Usage

import {  } from './viem.config'
 
const  = ..({
  : '0x20c0000000000000000000000000000000000000',
})
 
.(() => {
  for (const  of ) .(., .)
NextQuoteTokenSet {  updater: '0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266',  nextQuoteToken: '0x20C0000000000000000000000000000000000001'}
})
 
// Later, tear down the watcher.
.()

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

Recipes

Review Staged Quote Token Changes Before They Apply

Branch on eventName to flag a staged change for risk review while it is pending, then refresh pricing configuration once the update lands.

import {  } from './viem.config'
 
const  = ..({
  : '0x20c0000000000000000000000000000000000000',
})
 
.(() => {
  for (const  of ) {
    if (. === 'NextQuoteTokenSet')
      .('Review staged quote token:', ..)
    if (. === 'QuoteTokenUpdate')
      .('Quote token applied:', ..)
Review staged quote token: 0x20C0000000000000000000000000000000000001
  }
})

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. Discriminate the two events with eventName:

type Log =
  | {
      /** Decoded `NextQuoteTokenSet` event arguments. */
      args: {
        /** Address that staged the update. */
        updater: Address
        /** Quote token staged to apply. */
        nextQuoteToken: Address
      }
      /** Name of the emitted event. */
      eventName: 'NextQuoteTokenSet'
      // ...standard log fields (address, blockHash, blockNumber, logIndex, transactionHash, ...)
    }
  | {
      /** Decoded `QuoteTokenUpdate` event arguments. */
      args: {
        /** Address that applied the update. */
        updater: Address
        /** New quote token. */
        newQuoteToken: Address
      }
      /** Name of the emitted event. */
      eventName: 'QuoteTokenUpdate'
      // ...standard log fields (address, blockHash, blockNumber, logIndex, transactionHash, ...)
    }

Parameters

args

  • Type: object
type Args =
  | {
      /** Filter by updating address. */
      updater?: Address | Address[] | null
      /** Filter by staged quote token (`NextQuoteTokenSet`). */
      nextQuoteToken?: Address | Address[] | null
    }
  | {
      /** Filter by updating address. */
      updater?: Address | Address[] | null
      /** Filter by applied quote token (`QuoteTokenUpdate`). */
      newQuoteToken?: Address | Address[] | 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).

token

  • Type: Address | bigint

Token to operate on: a TIP-20 token id or a contract address.

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