watchContractEvent

Action that watches and returns emitted contract event logs.

Import

import { watchContractEvent } from '@wagmi/core'

Usage

index.tsabi.tsconfig.ts

import { watchContractEvent } from '@wagmi/core'
import { abi } from './abi'
import { config } from './config'

const unwatch = watchContractEvent(config, {
  address: '0x6b175474e89094c44da98b954eedeac495271d0f',
  abi,
  eventName: 'Transfer',
  onLogs(logs) {
    console.log('New logs!', logs)
  },
})
unwatch()

export const abi = [
  {
    type: 'event',
    name: 'Approval',
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
  {
    type: 'event',
    name: 'Transfer',
    inputs: [
      { indexed: true, name: 'from', type: 'address' },
      { indexed: true, name: 'to', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
] as const

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

Parameters

import { type WatchContractEventParameters } from '@wagmi/core'

abi

Abi

The contract's ABI. Check out the TypeScript docs for how to set up ABIs for maximum type inference and safety.

index.tsabi.tsconfig.ts

import { watchContractEvent } from '@wagmi/core'
import { abi } from './abi'
import { config } from './config'

const unwatch = watchContractEvent(config, {
  abi, 
  onLogs(logs) {
    console.log('Logs changed!', logs)
  },
})
unwatch()

export const abi = [
  {
    type: 'event',
    name: 'Approval',
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
  {
    type: 'event',
    name: 'Transfer',
    inputs: [
      { indexed: true, name: 'from', type: 'address' },
      { indexed: true, name: 'to', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
] as const

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

address

Address | undefined

The contract's address.

index.tsabi.tsconfig.ts

import { watchContractEvent } from '@wagmi/core'
import { abi } from './abi'
import { config } from './config'

const unwatch = watchContractEvent(config, {
  address: '0x6b175474e89094c44da98b954eedeac495271d0f', 
  abi,
  onLogs(logs) {
    console.log('Logs changed!', logs)
  },
})
unwatch()

export const abi = [
  {
    type: 'event',
    name: 'Approval',
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
  {
    type: 'event',
    name: 'Transfer',
    inputs: [
      { indexed: true, name: 'from', type: 'address' },
      { indexed: true, name: 'to', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
] as const

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

args

object | readonly unknown[] | undefined

Arguments to pass when calling the contract.
Inferred from abi and eventName.

index.tsabi.tsconfig.ts

import { watchContractEvent } from '@wagmi/core'
import { abi } from './abi'
import { config } from './config'

const unwatch = watchContractEvent(config, {
  abi,
  args: { 
    to: '0xd2135CfB216b74109775236E36d4b433F1DF507B', 
  }, 
  onLogs(logs) {
    console.log('Logs changed!', logs)
  },
})
unwatch()

export const abi = [
  {
    type: 'event',
    name: 'Approval',
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
  {
    type: 'event',
    name: 'Transfer',
    inputs: [
      { indexed: true, name: 'from', type: 'address' },
      { indexed: true, name: 'to', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
] as const

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

batch

boolean | undefined

Whether or not the events should be batched on each invocation.
Defaults to true.

index.tsabi.tsconfig.ts

import { watchContractEvent } from '@wagmi/core'
import { abi } from './abi'
import { config } from './config'

const unwatch = watchContractEvent(config, {
  abi,
  batch: false, 
  onLogs(logs) {
    console.log('Logs changed!', logs)
  },
})
unwatch()

export const abi = [
  {
    type: 'event',
    name: 'Approval',
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
  {
    type: 'event',
    name: 'Transfer',
    inputs: [
      { indexed: true, name: 'from', type: 'address' },
      { indexed: true, name: 'to', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
] as const

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

chainId

config['chains'][number]['id'] | undefined

ID of chain to use when fetching data.

index.tsabi.tsconfig.ts

import { watchContractEvent } from '@wagmi/core'
import { mainnet } from '@wagmi/core/chains'
import { abi } from './abi'
import { config } from './config'

const unwatch = watchContractEvent(config, {
  abi,
  chainId: mainnet.id, 
  onLogs(logs) {
    console.log('Logs changed!', logs)
  },
})
unwatch()

export const abi = [
  {
    type: 'event',
    name: 'Approval',
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
  {
    type: 'event',
    name: 'Transfer',
    inputs: [
      { indexed: true, name: 'from', type: 'address' },
      { indexed: true, name: 'to', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
] as const

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

eventName

string

Event to listen for the contract.
Inferred from abi.

index.tsabi.tsconfig.ts

import { watchContractEvent } from '@wagmi/core'
import { abi } from './abi'
import { config } from './config'

const unwatch = watchContractEvent(config, {
  abi,
  eventName: 'Approval', 
  onLogs(logs) {
    console.log('Logs changed!', logs)
  },
})
unwatch()

export const abi = [
  {
    type: 'event',
    name: 'Approval',
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
  {
    type: 'event',
    name: 'Transfer',
    inputs: [
      { indexed: true, name: 'from', type: 'address' },
      { indexed: true, name: 'to', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
] as const

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

onError

((error: Error) => void) | undefined

Error thrown from getting the block number.

index.tsabi.tsconfig.ts

import { watchContractEvent } from '@wagmi/core'
import { abi } from './abi'
import { config } from './config'

const unwatch = watchContractEvent(config, {
  abi,
  onLogs(logs) { 
    console.log('Logs changed!', logs) 
  }, 
  onError(error) { 
    console.error('Logs error', error) 
  }, 
})
unwatch()

export const abi = [
  {
    type: 'event',
    name: 'Approval',
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
  {
    type: 'event',
    name: 'Transfer',
    inputs: [
      { indexed: true, name: 'from', type: 'address' },
      { indexed: true, name: 'to', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
] as const

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

onLogs

(logs: Log[], prevLogs: Log[] | undefined) => void

Callback for when logs changes.

index.tsabi.tsconfig.ts

import { watchContractEvent } from '@wagmi/core'
import { abi } from './abi'
import { config } from './config'

const unwatch = watchContractEvent(config, {
  abi,
  onLogs(logs) { 
    console.log('Logs changed!', logs) 
  }, 
})
unwatch()

export const abi = [
  {
    type: 'event',
    name: 'Approval',
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
  {
    type: 'event',
    name: 'Transfer',
    inputs: [
      { indexed: true, name: 'from', type: 'address' },
      { indexed: true, name: 'to', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
] as const

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

poll

boolean | undefined

Whether or not to use a polling mechanism to check for new blocks instead of a WebSocket subscription.
Defaults to false for WebSocket Clients, and true for non-WebSocket Clients.

index.tsabi.tsconfig.ts

import { watchContractEvent } from '@wagmi/core'
import { abi } from './abi'
import { config } from './config'

const unwatch = watchContractEvent(config, {
  abi,
  onLogs(logs) {
    console.log('Logs changed!', logs)
  },
  poll: true, 
})
unwatch()

export const abi = [
  {
    type: 'event',
    name: 'Approval',
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
  {
    type: 'event',
    name: 'Transfer',
    inputs: [
      { indexed: true, name: 'from', type: 'address' },
      { indexed: true, name: 'to', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
] as const

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

pollingInterval

number | undefined

Polling frequency (in milliseconds).
Defaults to the Config's pollingInterval config.

index.tsabi.tsconfig.ts

import { watchContractEvent } from '@wagmi/core'
import { abi } from './abi'
import { config } from './config'

const unwatch = watchContractEvent(config, {
  abi,
  onLogs(logs) {
    console.log('Logs changed!', logs)
  },
  pollingInterval: 1_000, 
})
unwatch()

export const abi = [
  {
    type: 'event',
    name: 'Approval',
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
  {
    type: 'event',
    name: 'Transfer',
    inputs: [
      { indexed: true, name: 'from', type: 'address' },
      { indexed: true, name: 'to', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
] as const

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

strict

boolean | undefined

Defaults to false.

index.tsabi.tsconfig.ts

import { watchContractEvent } from '@wagmi/core'
import { abi } from './abi'
import { config } from './config'

const unwatch = watchContractEvent(config, {
  abi,
  onLogs(logs) {
    console.log('Logs changed!', logs)
  },
  strict: true, 
})
unwatch()

export const abi = [
  {
    type: 'event',
    name: 'Approval',
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
  {
    type: 'event',
    name: 'Transfer',
    inputs: [
      { indexed: true, name: 'from', type: 'address' },
      { indexed: true, name: 'to', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
] as const

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

syncConnectedChain

boolean | undefined

Set up subscriber for connected chain changes.
Defaults to Config['syncConnectedChain'].

index.tsabi.tsconfig.ts

import { watchContractEvent } from '@wagmi/core'
import { abi } from './abi'
import { config } from './config'

const unwatch = watchContractEvent(config, {
  abi,
  onLogs(logs) {
    console.log('Logs changed!', logs)
  },
  syncConnectedChain: false, 
})
unwatch()

export const abi = [
  {
    type: 'event',
    name: 'Approval',
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
  {
    type: 'event',
    name: 'Transfer',
    inputs: [
      { indexed: true, name: 'from', type: 'address' },
      { indexed: true, name: 'to', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' },
    ],
  },
] as const

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

Return Type

import { type WatchContractEventReturnType } from '@wagmi/core'

Function for cleaning up watcher.

Type Inference

With abi setup correctly, TypeScript will infer the correct types for eventName, args, and onLogs parameters. See the Wagmi TypeScript docs for more information.

Error

import { type WatchContractEventError } from '@wagmi/core'

TanStack Query

import {
  type WatchContractEventData,
  type WatchContractEventOptions,
  type WatchContractEventQueryFnData,
  type WatchContractEventQueryKey,
  watchContractEventQueryKey,
  watchContractEventQueryOptions,
} from '@wagmi/core/query'

Viem

watchContractEvent

Connectors

Transports

watchContractEvent

Import

Usage

Parameters

abi

address

args

batch

chainId

eventName

onError

onLogs

poll

pollingInterval

strict

syncConnectedChain

Return Type

Type Inference

Error

TanStack Query

Viem

watchContractEvent ​

Import ​

Usage ​

Parameters ​

abi ​

address ​

args ​

batch ​

chainId ​

eventName ​

onError ​

onLogs ​

poll ​

pollingInterval ​

strict ​

syncConnectedChain ​

Return Type ​

Type Inference ​

Error ​

TanStack Query ​

Viem ​

watchContractEvent

Import

Usage

Parameters

abi

address

args

batch

chainId

eventName

onError

onLogs

poll

pollingInterval

strict

syncConnectedChain

Return Type

Type Inference

Error

TanStack Query

Viem