# eip712HashType

Description: eip712HashType cheatcode documentation

Note: This document was authored using MDX

  Source: https://github.com/NomicFoundation/hardhat-website/tree/main/src/content/docs/docs/reference/cheatcodes/Utilities/eip712-hash-type.mdx

### Signature

```solidity
function eip712HashType(
  string calldata typeNameOrDefinition
) external pure returns (bytes32);
```

### Description

Returns `keccak256(bytes(canonicalTypeString))` for the given EIP-712 type.

The argument can be a registered struct name (e.g. `"Mail"`) or a full EIP-712 type definition string.

> **Note:** Requires the `test.solidity.eip712Types` configuration. See the [EIP-712 type hashing guide](/docs/guides/testing/eip712-types) for setup.

### Examples

```solidity
// Look up by registered name
bytes32 hash = cheats.eip712HashType("Mail");

// Or pass a full type definition directly
bytes32 hash2 = cheats.eip712HashType(
    "Mail(Person from,Person to,string contents)Person(address wallet,string name)"
);

assertEq(hash, hash2);
```

### SEE ALSO

- [eip712HashStruct](/docs/reference/cheatcodes/utilities/eip712-hash-struct)
- [eip712HashTypedData](/docs/reference/cheatcodes/utilities/eip712-hash-typed-data)
- [EIP-712 type hashing guide](/docs/guides/testing/eip712-types)