Tevm actions & JSON-RPC

An ethers provider can only do what a remote node exposes. TevmProvider also gives you direct access to the EVM behind it through provider.tevm, and through the tevm_* JSON-RPC methods on provider.send.

`provider.tevm`

provider.tevm is the Tevm node extended with tevmActions() and tevmSend():

Action	What it does
`call`	Execute a message call with fine-grained control over state and tracing.
`contract`	Execute a call encoded from an ABI and decode the result.
`deploy`	Deploy bytecode, optionally adding the tx to a block.
`deal`	Give an account ETH or an ERC20 balance by writing storage.
`mine`	Mine one or more blocks.
`getAccount`	Read balance, nonce, code, and storage root of an account.
`setAccount`	Overwrite balance, nonce, and deployed bytecode of an account.
`dumpState`	Serialize the whole EVM state.
`loadState`	Restore a previously dumped state.
`send` / `sendBulk`	Raw JSON-RPC against the node.

Reading and writing accounts

import {  } from '@tevm/ethers'
 
const  = await .createMemoryProvider({})
 
await .tevm.setAccount({
	: `0x${'69'.(20)}`,
	: 420n,
})
 
const  = await .tevm.getAccount({ : `0x${'69'.(20)}` })
 
.(.balance) // 420n
.(.isContract) // false

Executing a contract call without deploying

setAccount can install bytecode at any address, so you can execute a contract that was never deployed by a transaction.

import {  } from '@tevm/ethers'
import {  } from '@tevm/contract'
 
const  = await .createMemoryProvider({})
 
const  = ({
	: 'AddContract',
	: ['function add(uint256 a, uint256 b) public pure returns (uint256)'],
	: `0x${'42'.(20)}`,
	:
		'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',
})
 
await .tevm.setAccount({
	: .,
	: .,
})
 
const  = await .tevm.contract(..add(390n, 30n))
 
.(.data) // 420n
.(.executionGasUsed) // gas used by the call

Mining

import {  } from '@tevm/ethers'
 
const  = await .createMemoryProvider({})
 
await .tevm.mine({ : 3 })
 
.(await .getBlockNumber()) // 3

`tevm_*` JSON-RPC methods

Everything above is also reachable over JSON-RPC, which matters when the provider is the only object you can pass around (for example, inside a library that accepts an EIP-1193 provider).

import {  } from '@tevm/ethers'
import {  } from '@tevm/utils'
 
const  = await .createMemoryProvider({})
 
await .send('tevm_setAccount', [
	{
		: `0x${'69'.(20)}`,
		: (1n),
		: (420n),
	},
])
 
const  = await .send('tevm_getAccount', [{ : `0x${'69'.(20)}` }])
 
.(.balance) // '0x1a4'
.(.nonce) // '0x1'

Available methods: tevm_call, tevm_getAccount, tevm_setAccount, tevm_mine, tevm_dumpState, tevm_loadState. Standard eth_* and anvil_*/debug_* methods supported by the node work too.

Persisting and restoring state

import {  } from '@tevm/ethers'
 
const  = await .createMemoryProvider({})
 
await .tevm.setAccount({ : `0x${'42'.(20)}`, : 100n })
 
const  = await .tevm.dumpState()
 
const  = await .createMemoryProvider({})
await .tevm.loadState({ : .state })
 
.(await .getBalance(`0x${'42'.(20)}`)) // 100n

Because the dump is plain JSON you can write it to disk and reuse it as a test fixture — see Forking a network.

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