diff options
| -rw-r--r-- | packages/order-utils/src/index.ts | 1 | ||||
| -rw-r--r-- | packages/order-utils/src/rate_utils.ts | 44 |
2 files changed, 45 insertions, 0 deletions
diff --git a/packages/order-utils/src/index.ts b/packages/order-utils/src/index.ts index 858f500c6..a52f936b6 100644 --- a/packages/order-utils/src/index.ts +++ b/packages/order-utils/src/index.ts @@ -33,3 +33,4 @@ export { EIP712Utils } from './eip712_utils'; export { OrderValidationUtils } from './order_validation_utils'; export { ExchangeTransferSimulator } from './exchange_transfer_simulator'; export { marketUtils } from './market_utils'; +export { rateUtils } from './rate_utils'; diff --git a/packages/order-utils/src/rate_utils.ts b/packages/order-utils/src/rate_utils.ts new file mode 100644 index 000000000..212431e0c --- /dev/null +++ b/packages/order-utils/src/rate_utils.ts @@ -0,0 +1,44 @@ +import { schemas } from '@0xproject/json-schemas'; +import { SignedOrder } from '@0xproject/types'; +import { BigNumber } from '@0xproject/utils'; + +import { assert } from './assert'; +import { constants } from './constants'; + +export const rateUtils = { + /** + * Takes a signed order and calculates the fee adjusted rate (takerAsset/makerAsset) by calculating how much takerAsset + * is required to cover the fees (feeRate * takerFee), adding the takerAssetAmount and dividing by makerAssetAmount + * @param signedOrder An object that conforms to the signedOrder interface + * @param feeRate The market rate of ZRX denominated in takerAssetAmount + * (ex. feeRate is 0.1 takerAsset/ZRX if it takes 1 unit of takerAsset to buy 10 ZRX) + * @return The rate (takerAsset/makerAsset) of the order adjusted for fees + */ + getFeeAdjustedRateOfOrder(signedOrder: SignedOrder, feeRate: BigNumber): BigNumber { + assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema); + assert.isBigNumber('feeRate', feeRate); + assert.assert(feeRate.greaterThan(constants.ZERO_AMOUNT), `Expected feeRate: ${feeRate} to be greater than 0`); + const takerAssetAmountNeededToPayForFees = signedOrder.takerFee.mul(feeRate); + const totalTakerAssetAmount = takerAssetAmountNeededToPayForFees.plus(signedOrder.takerAssetAmount); + const rate = totalTakerAssetAmount.div(signedOrder.makerAssetAmount); + return rate; + }, + /** + * Takes a signed fee order (makerAssetData corresponds to ZRX and takerAssetData corresponds to WETH) and calculates + * the fee adjusted rate (WETH/ZRX) by dividing the takerAssetAmount by the makerAmount minus the takerFee + * @param signedFeeOrder An object that conforms to the signedOrder interface + * @return The rate (WETH/ZRX) of the fee order adjusted for fees + */ + getFeeAdjustedRateOfFeeOrder(signedFeeOrder: SignedOrder): BigNumber { + assert.doesConformToSchema('signedFeeOrder', signedFeeOrder, schemas.signedOrderSchema); + const zrxAmountAfterFees = signedFeeOrder.makerAssetAmount.sub(signedFeeOrder.takerFee); + assert.assert( + zrxAmountAfterFees.greaterThan(constants.ZERO_AMOUNT), + `Expected takerFee: ${JSON.stringify( + signedFeeOrder.takerFee, + )} to be less than makerAssetAmount: ${JSON.stringify(signedFeeOrder.makerAssetAmount)}`, + ); + const rate = signedFeeOrder.takerAssetAmount.div(zrxAmountAfterFees); + return rate; + }, +}; |