DutchAuctionWrapper is not decoding correctly

[fvictorio]

Expected Behavior

Encoding some data with DutchAuctionWrapper.encodeDutchAuctionAssetData and then decoding it with DutchAuctionWrapper.decodeDutchAuctionAssetData should give back the same arguments that were used during the encoding.

Current Behavior

const data = DutchAuctionWrapper.encodeDutchAuctionAssetData(wethAssetData, new BigNumber('1557853498'), new BigNumber('1000000000000000000'))
// data is '0xf47261b00000000000000000000000000b1ba0af832d7c05fd64161e0db78e85978e8082000000000000000000000000000000000000000000000000000000005cdaf53a0000000000000000000000000000000000000000000000000de0b6b3a7640000'
const decoded = DutchAuctionWrapper.decodeDutchAuctionData(data)
// decoded is {
//    assetData: { assetProxyId: '0xf47261b0', tokenAddress: '0x0b1ba0af832d7c05fd64161e0db78e85978e8082' },
//    beginTimeSeconds: 91662660760,
//    beginAmount: 4722366482869645213696
// }

Notice that beginTimeSeconds is 1557853498 (the original argument) interpreted as hex:

> 0x1557853498
91662660760

The same happens with beginAmount.

Possible Solution

I think the problem might be here:

0x-monorepo/packages/contract-wrappers/src/contract_wrappers/dutch_auction_wrapper.ts

Lines 74 to 75 in 418d033

	const beginTimeSeconds = new BigNumber(`0x${beginTimeSecondsAsBN.toString()}`);
	const beginAmount = new BigNumber(`0x${beginAmountAsBN.toString()}`);

After getting the decoded data, a BigNumber is created by prepending 0x to it.

Your Environment

Package	Version
0x.js	6.0.7