Appearance

createEventFilter ​

Creates a Filter to listen for new events that can be used with getFilterChanges.

Usage ​

By default, an Event Filter with no arguments will query for/listen to all events.

ts
import { publicClient } from './client'

const filter = await publicClient.createEventFilter()
// { id: "0x345a6572337856574a76364e457a4366", type: 'event' }
import { publicClient } from './client'

const filter = await publicClient.createEventFilter()
// { id: "0x345a6572337856574a76364e457a4366", type: 'event' }
ts
import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

export const publicClient = createPublicClient({
  chain: mainnet,
  transport: http()
})
import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

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

TIP

Check out createContractEventFilter if you are after a first-class solution for querying events on a contract without needing to manually craft ABI event parameters.

Scoping ​

You can also scope a Filter to a set of given attributes (listed below).

Address ​

A Filter can be scoped to an address:

ts
import { publicClient } from './client'

const filter = await publicClient.createEventFilter({
  address: '0xfba3912ca04dd458c843e2ee08967fc04f3579c2' 
})
import { publicClient } from './client'

const filter = await publicClient.createEventFilter({
  address: '0xfba3912ca04dd458c843e2ee08967fc04f3579c2' 
})
ts
import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

export const publicClient = createPublicClient({
  chain: mainnet,
  transport: http()
})
import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

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

Event ​

A Filter can be scoped to an event.

The event argument takes in an event in ABI format – we have a parseAbiItem utility that you can use to convert from a human-readable event signature → ABI.

ts
import { parseAbiItem } from 'viem' 
import { publicClient } from './client'

const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'), 
})
import { parseAbiItem } from 'viem' 
import { publicClient } from './client'

const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'), 
})
ts
import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

export const publicClient = createPublicClient({
  chain: mainnet,
  transport: http()
})
import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

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

By default, event accepts the AbiEvent type:

ts
import { publicClient } from './client'

const filter = await publicClient.createEventFilter(publicClient, {
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: { 
    name: 'Transfer', 
    inputs: [
      { type: 'address', indexed: true, name: 'from' },
      { type: 'address', indexed: true, name: 'to' },
      { type: 'uint256', indexed: false, name: 'value' }
    ] 
  }
})
import { publicClient } from './client'

const filter = await publicClient.createEventFilter(publicClient, {
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: { 
    name: 'Transfer', 
    inputs: [
      { type: 'address', indexed: true, name: 'from' },
      { type: 'address', indexed: true, name: 'to' },
      { type: 'uint256', indexed: false, name: 'value' }
    ] 
  }
})
ts
import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

export const publicClient = createPublicClient({
  chain: mainnet,
  transport: http()
})
import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

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

Arguments ​

A Filter can be scoped to given indexed arguments:

ts
const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'),
  args: { 
    from: '0xd8da6bf26964af9d7eed9e03e53415d37aa96045',
    to: '0xa5cc3c03994db5b0d9a5eedd10cabab0813678ac'
  }
})
const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'),
  args: { 
    from: '0xd8da6bf26964af9d7eed9e03e53415d37aa96045',
    to: '0xa5cc3c03994db5b0d9a5eedd10cabab0813678ac'
  }
})

Only indexed arguments in event are candidates for args.

A Filter Argument can also be an array to indicate that other values can exist in the position:

ts
const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'),
  args: { 
    // '0xd8da...' OR '0xa5cc...' OR '0xa152...'
    from: [
      '0xd8da6bf26964af9d7eed9e03e53415d37aa96045', 
      '0xa5cc3c03994db5b0d9a5eedd10cabab0813678ac',
      '0xa152f8bb749c55e9943a3a0a3111d18ee2b3f94e',
    ],
  }
})
const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'),
  args: { 
    // '0xd8da...' OR '0xa5cc...' OR '0xa152...'
    from: [
      '0xd8da6bf26964af9d7eed9e03e53415d37aa96045', 
      '0xa5cc3c03994db5b0d9a5eedd10cabab0813678ac',
      '0xa152f8bb749c55e9943a3a0a3111d18ee2b3f94e',
    ],
  }
})

Block Range ​

A Filter can be scoped to a block range:

ts
const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'),
  fromBlock: 16330000n, 
  toBlock: 16330050n 
})
const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'),
  fromBlock: 16330000n, 
  toBlock: 16330050n 
})

Multiple Events ​

A Filter can be scoped to multiple events:

ts
const filter = await publicClient.createEventFilter({
  events: parseAbi([ 
    'event Approval(address indexed owner, address indexed sender, uint256 value)',
    'event Transfer(address indexed from, address indexed to, uint256 value)',
  ]),
})
const filter = await publicClient.createEventFilter({
  events: parseAbi([ 
    'event Approval(address indexed owner, address indexed sender, uint256 value)',
    'event Transfer(address indexed from, address indexed to, uint256 value)',
  ]),
})

Note: A Filter scoped to multiple events cannot be also scoped with indexed arguments (args).

Strict Mode ​

By default, createEventFilter will include logs that do not conform to the indexed & non-indexed arguments on the event. viem will not return a value for arguments that do not conform to the ABI, thus, some arguments on args may be undefined.

ts
const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'),
})
const logs = await publicClient.getFilterLogs({ filter })

logs[0].args
//      ^? { address?: Address, to?: Address, value?: bigint }
const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'),
})
const logs = await publicClient.getFilterLogs({ filter })

logs[0].args
//      ^? { address?: Address, to?: Address, value?: bigint }

You can turn on strict mode to only return logs that conform to the indexed & non-indexed arguments on the event, meaning that args will always be defined. The trade-off is that non-conforming logs will be filtered out.

ts
const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'),
  strict: true
})
const logs = await publicClient.getFilterLogs({ logs })

logs[0].args
//      ^? { address: Address, to: Address, value: bigint }
const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'),
  strict: true
})
const logs = await publicClient.getFilterLogs({ logs })

logs[0].args
//      ^? { address: Address, to: Address, value: bigint }

Returns ​

Filter

Parameters ​

address (optional) ​

  • Type: Address | Address[]

The contract address or a list of addresses from which Logs should originate.

ts
const filter = await publicClient.createEventFilter({
  address: '0xfba3912ca04dd458c843e2ee08967fc04f3579c2' 
})
const filter = await publicClient.createEventFilter({
  address: '0xfba3912ca04dd458c843e2ee08967fc04f3579c2' 
})

event (optional) ​

The event in ABI format.

A parseAbiItem utility is exported from viem that converts from a human-readable event signature → ABI.

ts
import { parseAbiItem } from 'viem' 

const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'), 
})
import { parseAbiItem } from 'viem' 

const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'), 
})

args (optional) ​

  • Type: Inferred.

A list of indexed event arguments.

ts
const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'),
  args: { 
    from: '0xd8da6bf26964af9d7eed9e03e53415d37aa96045',
    to: '0xa5cc3c03994db5b0d9a5eedd10cabab0813678ac'
  }
})
const filter = await publicClient.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed from, address indexed to, uint256 value)'),
  args: { 
    from: '0xd8da6bf26964af9d7eed9e03e53415d37aa96045',
    to: '0xa5cc3c03994db5b0d9a5eedd10cabab0813678ac'
  }
})

fromBlock (optional) ​

  • Type: bigint

Block to start querying/listening from.

ts
const filter = await publicClient.createEventFilter({
  fromBlock: 69420n 
})
const filter = await publicClient.createEventFilter({
  fromBlock: 69420n 
})

toBlock (optional) ​

  • Type: bigint

Block to query/listen until.

ts
const filter = await publicClient.createEventFilter({
  fromBlock: 70120n 
})
const filter = await publicClient.createEventFilter({
  fromBlock: 70120n 
})

JSON-RPC Methods ​

eth_newFilter

Released under the MIT License.

Copyright © 2023-present weth, LLC