Function encodeMetaApprovalData

tests/utils/helpers.ts:290–346

(a: ApprovalSignature, domainHash: string, gasReceipt?: GasReceipt | null, sigType?: string)

// Encode data that is passed to safeTransferFrom() for metaTransfers
export async function encodeMetaApprovalData(a: ApprovalSignature, domainHash: string, gasReceipt?: GasReceipt | null, sigType?: string) 
{
  const META_APPROVAL_TYPEHASH = "0xf5d4c820494c8595de274c7ff619bead38aac4fbc3d143b5bf956aa4b84fa524";

  let sigData: string; // Data to sign
  let txDataTypes: string[]; // Types of data to encode
  let sig: string; // Signature

  const approved_hex = a.approved ? '0x1' : '0x0'
  const is_gas_Fee_hex = a.isGasFee ? '0x1' : '0x0'

  // Struct Data type
  const sigArgTypes = [
    'bytes32', // META_TX_TYPEHASH
    'uint256', // _owner: uint256(address)
    'uint256', // _operator: uint256(address)
    'uint256', // _approved: uint256(bool)
    'uint256', // _isGasFee: uint256(bool)
    'uint256', // nonce
  ];
  
  // Get signer
  const signer = a.owner ? a.owner : await a.signerWallet.getAddress()

  // Packed encoding of transfer signature message
  sigData = ethers.utils.solidityPack(sigArgTypes, [
    META_APPROVAL_TYPEHASH,
    signer,
    a.operator,
    approved_hex,
    is_gas_Fee_hex,
    a.nonce,
  ])

  txDataTypes = ['bytes', 'bytes']; // (sig, (gasReceipt))
  
  // When gas receipt is included
  if (gasReceipt && gasReceipt !== null) {
    const gasData = utils.defaultAbiCoder.encode([GasReceiptType], [gasReceipt])
    sigData = ethers.utils.keccak256(ethers.utils.solidityPack(
      ['bytes', 'bytes32'], 
      [sigData, ethers.utils.keccak256(gasData)] //Hash of _data
    ))
    sig = await ethSignTypedData(a.signerWallet, domainHash,  sigData, a.nonce, sigType)
    return  utils.defaultAbiCoder.encode(txDataTypes, [sig, gasData])
    
  } else { 
    const emptyTransferData = []
    sigData = ethers.utils.keccak256(ethers.utils.solidityPack(
      ['bytes', 'bytes32'], 
      [sigData, ethers.utils.keccak256(emptyTransferData)] //Hash of _data
    ))
    sig = await ethSignTypedData(a.signerWallet, domainHash,  sigData, a.nonce, sigType)
    return  utils.defaultAbiCoder.encode(txDataTypes, [sig, emptyTransferData])
  }

}