just a simple function to transform a typical 0x order object into the form we need.

transform.js

const transform = ({
  exchangeContract,
  expiration,
  feeRecipient,
  salt,
  maker,
  taker
}) => ({
  exchangeContractAddress: exchangeContract,
  expirationUnixTimestampSec: expiration,
  feeRecipient: feeRecipient,
  maker: maker.address,
  makerFee: maker.feeAmount,
  makerTokenAddress: maker.token.address,
  makerTokenAmount: maker.amount,
  salt: salt,
  taker: taker.address,
  takerFee: taker.feeAmount,
  takerTokenAddress: taker.token.address,
  takerTokenAmount: taker.amount
})

// Example input/output below

const example0xOrder = {  
   "maker":{  
      "address":"0x201c6c7e32fad71d2e8c554958a2283a62a67a48",
      "token":{  
         "name":"Aragon",
         "symbol":"ANT",
         "decimals":18,
         "address":"0x960b236a07cf122663c4303350609a66a7b288c0"
      },
      "amount":"20345000000000000000",
      "feeAmount":"0"
   },
   "taker":{  
      "address":"",
      "token":{  
         "name":"Ether Token",
         "symbol":"WETH",
         "decimals":18,
         "address":"0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"
      },
      "amount":"129000000000000000",
      "feeAmount":"0"
   },
   "expiration":"1515441600",
   "feeRecipient":"0x0000000000000000000000000000000000000000",
   "salt":"37090108066070358564552859386421900033660410305386203610878278899066621444429",
   "signature":{  
      "v":27,
      "r":"0xbaad473ee3adbcdf1f946e4c219684d06c0193049f07002fa91b04329cd75b12",
      "s":"0x06d65682fbe24a83e9f30634923af25056217038dec60d9166af52f5e299637a",
      "hash":"0xf6c0468b241861b82e781b297ce641f86bc715316804e0677d87fd250ed9da28"
   },
   "exchangeContract":"0x12459c951127e0c374ff9105dda097662a027093",
   "networkId":1
}

console.log(transform(example0xOrder))

// { exchangeContractAddress: '0x12459c951127e0c374ff9105dda097662a027093',
//   expirationUnixTimestampSec: '1515441600',
//   feeRecipient: '0x0000000000000000000000000000000000000000',
//   maker: '0x201c6c7e32fad71d2e8c554958a2283a62a67a48',
//   makerFee: '0',
//   makerTokenAddress: '0x960b236a07cf122663c4303350609a66a7b288c0',
//   makerTokenAmount: '20345000000000000000',
//   salt: '37090108066070358564552859386421900033660410305386203610878278899066621444429',
//   taker: '',
//   takerFee: '0',
//   takerTokenAddress: '0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2',
//   takerTokenAmount: '129000000000000000' }