createEventFilter

An Action for creating a new Event Filter.

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.

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

Scoping

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

Address

A Filter can be scoped to an address:

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

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.

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

By default, event accepts the AbiEvent type:

// @filename: client.ts
import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'
 
export const publicClient = createPublicClient({
  chain: mainnet,
  transport: http()
})
// @filename: example.ts
// ---cut---
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' }
    ] 
  }
})

Arguments

A Filter can be scoped to given indexed arguments:

import {  } from 'viem'
 
const  = await .({
  : '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  : ('event Transfer(address indexed from, address indexed to, uint256 value)'),
  : { 
    : '0xd8da6bf26964af9d7eed9e03e53415d37aa96045',
    : '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:

import {  } from 'viem'
 
const  = await .({
  : '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  : ('event Transfer(address indexed from, address indexed to, uint256 value)'),
  : { 
    // '0xd8da...' OR '0xa5cc...' OR '0xa152...'
    : [
      '0xd8da6bf26964af9d7eed9e03e53415d37aa96045', 
      '0xa5cc3c03994db5b0d9a5eedd10cabab0813678ac',
      '0xa152f8bb749c55e9943a3a0a3111d18ee2b3f94e',
    ],
  }
})

Block Range

A Filter can be scoped to a block range:

import {  } from 'viem'
 
const  = await .({
  : '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  : ('event Transfer(address indexed from, address indexed to, uint256 value)'),
  : 16330000n, 
  : 16330050n
})

Multiple Events

A Filter can be scoped to multiple events:

import {  } from 'viem'
 
const  = await .({
  : ([ 
    '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.

import {  } from 'viem'
 
const  = await .({
  : '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  : ('event Transfer(address indexed from, address indexed to, uint256 value)'),
})
const  = await .({  })
 
[0].

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.

import {  } from 'viem'
 
const  = await .({
  : '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  : ('event Transfer(address indexed from, address indexed to, uint256 value)'),
  : true
})
const  = await .({  })
 
[0].

Returns

Filter

Parameters

address (optional)

Type: Address | Address[]

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

const  = await .({
  : '0xfba3912ca04dd458c843e2ee08967fc04f3579c2'
})

event (optional)

Type: AbiEvent

The event in ABI format.

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

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

args (optional)

Type: Inferred.

A list of indexed event arguments.

import {  } from 'viem'
 
const  = await .({
  : '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  : ('event Transfer(address indexed from, address indexed to, uint256 value)'),
  : { 
    : '0xd8da6bf26964af9d7eed9e03e53415d37aa96045',
    : '0xa5cc3c03994db5b0d9a5eedd10cabab0813678ac'
  }
})

fromBlock (optional)

Type: bigint

Block to start querying/listening from.

const  = await .({
  : 69420n
})

toBlock (optional)

Type: bigint

Block to query/listen until.

const  = await .({
  : 70120n
})

JSON-RPC Methods

eth_newFilter

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