Rumpel Merklization

merklize.ts

import { Address, encodePacked, keccak256 } from "viem";

import { MerkleTree } from "merkletreejs";

const solidityKeccak256 = (types: string[], values: any[]) => {
  return keccak256(encodePacked(types, values));
};

export type Distribution = {
  [user: Address]: {
    [pointsId: `0x${string}`]: {
      accumulatingPoints: bigint;
     };
   };
};

export type MerklizedDistribution = Distribution & {
  [user: Address]: {
    [pointsId: `0x${string}`]: {
      proof: string[];
    };
  };
  root: string;
};

export function merklizeDistribution(
  distribution: Distribution
): MerklizedDistribution {
  const leaves = Object.entries(distribution).flatMap(([user, pointsIds]) =>
    Object.entries(pointsIds).map(([pointsId, { accumulatingPoints }]) =>
      solidityKeccak256(
        ["address", "bytes32", "uint256"],
        [user, pointsId, accumulatingPoints]
      )
    )
  );

  if (leaves.length === 0) {
    return { root: "0x", ...distribution };
  } else if (leaves.length === 1) {
    leaves.push(leaves[0]);
  }

  const tree = new MerkleTree(leaves, keccak256, { sortPairs: true });
  const root = tree.getHexRoot();

  for (const [user, pointsIds] of Object.entries(distribution)) {
    for (const [pointsId, userPoints] of Object.entries(pointsIds)) {
      const leaf = solidityKeccak256(
        ["address", "bytes32", "uint256"],
        [user, pointsId, userPoints.accumulatingPoints]
      );
      // @ts-ignore
      userPoints.proof = tree.getHexProof(leaf);
    }
  }

  return { root, ...distribution };
}