const tokenAddress = "0x1234..."
const holderAddress = "0x2345..."
const balancePositionIdx = 1

const balanceSlot = ERC20Proof.getHolderBalanceSlot(holderAddress, balancePositionIdx)

const result = await ERC20Proof.get(tokenAddress, [balanceSlot], blockNumber, jsonRpcUri)

const { proof, block, blockHeaderRLP, accountProofRLP, storageProofsRLP } = result

// Throws if not valid
await ERC20Proof.verify(block.stateRoot, tokenAddress, proof)

// ...