watchContractEvent

Watches and returns emitted contract event logs.

This Action will batch up all the event logs found within the pollingInterval, and invoke them via onLogs.

watchContractEvent will attempt to create an Event Filter and listen to changes to the Filter per polling interval, however, if the RPC Provider does not support Filters (ie. eth_newFilter), then watchContractEvent will fall back to using getLogs instead.

Usage

example.tsclient.ts

import { publicClient } from './client'
import { wagmiAbi } from './abi'

const unwatch = await publicClient.watchContractEvent({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: wagmiAbi,
  onLogs: logs => console.log(logs)
})
// > [{ ... }, { ... }, { ... }]
// > [{ ... }, { ... }]
// > [{ ... }, { ... }, { ... }, { ... }]

import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

export const publicClient = createPublicClient({
  chain: mainnet,
  transport: http()
})

Scoping to an Event Name

You can scope to an event on the given ABI.

example.tsabi.tsclient.ts

import { publicClient } from './client'
import { wagmiAbi } from './abi'

const unwatch = await publicClient.watchContractEvent({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: wagmiAbi,
  eventName: 'Transfer',
  onLogs: logs => console.log(logs)
})
// > [{ ... }, { ... }, { ... }]
// > [{ ... }, { ... }]
// > [{ ... }, { ... }, { ... }, { ... }]

export const wagmiAbi = [
  ...
  {
    inputs: [
      {
        indexed: true,
        name: "from",
        type: "address",
      },
      { indexed: true, name: "to", type: "address" },
      {
        indexed: true,
        name: "tokenId",
        type: "uint256",
      },
    ],
    name: "Transfer",
    type: "event",
  },
  ...
] as const;

import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

export const publicClient = createPublicClient({
  chain: mainnet,
  transport: http()
})

Scoping to Event Arguments

You can scope to given indexed event arguments.

In the example below, we want to filter out Transfers that were sent by the address "0xc961145a54C96E3aE9bAA048c4F4D6b04C13916b".

Only indexed arguments on the event ABI are candidates for args (see abi.ts).

example.tsabi.tsclient.ts

import { publicClient } from './client'
import { wagmiAbi } from './abi'

const unwatch = await publicClient.watchContractEvent({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: wagmiAbi,
  eventName: 'Transfer',
  args: { from: '0xc961145a54C96E3aE9bAA048c4F4D6b04C13916b' },
  onLogs: logs => console.log(logs)
})
// > [{ ... }, { ... }, { ... }]
// > [{ ... }, { ... }]
// > [{ ... }, { ... }, { ... }, { ... }]

export const wagmiAbi = [
  ...
  {
    inputs: [
      {
        indexed: true,
        name: "from",
        type: "address",
      },
      { 
        indexed: true, 
        name: "to", 
        type: "address" 
      },
      {
        indexed: false,
        name: "tokenId",
        type: "uint256",
      },
    ],
    name: "Transfer",
    type: "event",
  },
  ...
] as const;

import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

export const publicClient = createPublicClient({
  chain: mainnet,
  transport: http()
})

Returns

UnwatchFn

A function that can be invoked to stop watching for new event logs.

Arguments

abi

Type: Abi

The contract's ABI.

const unwatch = await publicClient.watchContractEvent({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: wagmiAbi, 
  onLogs: logs => console.log(logs)
})

onLogs

Type: (Log[]) => void

The new event logs.

const unwatch = await publicClient.watchContractEvent({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: wagmiAbi,
  onLogs: logs => console.log(logs) 
})

address (optional)

Type: Address

The contract address. If no address is provided, then it will emit all events matching the event signatures on the ABI.

const unwatch = await publicClient.watchContractEvent({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2', 
  abi: wagmiAbi,
  onLogs: logs => console.log(logs)
})

args (optional)

Type: Inferred from ABI.

Event arguments to filter logs.

const unwatch = await publicClient.watchContractEvent({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: wagmiAbi,
  eventName: 'Transfer', 
  args: ['0xc961145a54C96E3aE9bAA048c4F4D6b04C13916b'], 
  onLogs: logs => console.log(logs)
})

eventName (optional)

Type: string

An event name to filter logs.

const unwatch = await publicClient.watchContractEvent({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: wagmiAbi,
  eventName: 'Transfer', 
  onLogs: logs => console.log(logs)
})

batch (optional)

Type: boolean
Default: true

Whether or not to batch logs between polling intervals.

const unwatch = await publicClient.watchContractEvent({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: wagmiAbi,
  batch: false, 
  onLogs: logs => console.log(logs)
})

onError (optional)

Type: (error: Error) => void

Error thrown from listening for new event logs.

const unwatch = await publicClient.watchContractEvent({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: wagmiAbi,
  onError: error => console.log(error), 
  onLogs: logs => console.log(logs)
})

pollingInterval (optional)

Type: number

Polling frequency (in ms). Defaults to the Client's pollingInterval config.

const unwatch = await publicClient.watchContractEvent({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: wagmiAbi,
  pollingInterval: 1_000, 
  onLogs: logs => console.log(logs)
})

watchContractEvent #

Usage #

Scoping to an Event Name #

Scoping to Event Arguments #

Returns #

Arguments #

abi #

onLogs #

address (optional) #

args (optional) #

eventName (optional) #

batch (optional) #

onError (optional) #

pollingInterval (optional) #