Merkletreejs hash does not match expected Solidity keccak hash

[QEDK]

I presume this is because the hexstring is parsed as text, for e.g. this tree:

└─ 7bd62a75d6e486a759d2060beeaaa851c1bb46427fa155a3b09d7895a761f58b
   ├─ e9e8231adc2ecb81d80587742818d309b6cdfc3fb4abb09eeab4f8b8492bd58a
   │  ├─ 8b117e8553a17ab37aba92ae84cc97a7d4df9aebce486b72741df499cb04a344
   │  └─ 9214d159784576263b97979db3f50143f3314f118237c8ec2c9ed005589e93de
   └─ 2299a49e35aeeb95f3e0466bc143bc6df56ab5e13b8c6d191614a966122a0d63
      ├─ 57b7579accf9fdd32ca51f776a3d032dd6dcfea6a4a83ba304de30e12a7db68e
      └─ 06c6b07877bcb499d6952d8e1503e591a64f476a6c35beb93d601eccd48f4a1a

If you put in the first two leaves concatenated on https://emn178.github.io/online-tools/keccak_256.html it would actually be f68b7c2821ff5479150c5204d6671eb40a33748a1d2e5becc7b34dc17964dad1 which matches the Solidity output of keccak256(abi.encodePacked(leaf1,leaf2))

For some additional context, I have a struct like:

Obj {
 id: uint256,
 ...
}

This is then encoded in Solidity like keccak256(abi.encode(objs)) and is used as the leaf. The leaf encoding is correct (verified using debugger) and the entire process works fine in Solidity, except that each hash does not agree to the one produced by Solidity.

Here's the code I am using to run this:

import { keccak256 } from "keccak256";
...
tree = new MerkleTree(hashes, keccak256); // hashes is array of keccak256(abi.encode(objs)) 
const root = tree.getHexRoot();
console.log(tree.toString());

hashes looks like:

[
  '0x8b117e8553a17ab37aba92ae84cc97a7d4df9aebce486b72741df499cb04a344',
  '0x9214d159784576263b97979db3f50143f3314f118237c8ec2c9ed005589e93de',
  '0x57b7579accf9fdd32ca51f776a3d032dd6dcfea6a4a83ba304de30e12a7db68e',
  '0x06c6b07877bcb499d6952d8e1503e591a64f476a6c35beb93d601eccd48f4a1a'
]

[esorey]

Ran into something similar - try dropping the object-based import of keccak256, like so:

import keccak256 from "keccak256"

Assuming that that does the trick, this seems to actually be an issue with how keccak256 exports its functions - very surprising, not good.