Add function to get gas price as hex string

src/feeOracle.ts

@@ -60,7 +60,7 @@ export abstract class TornadoFeeOracle implements ITornadoFeeOracle {
    * @param {TxType} type Tornado transaction type (to select correct default bump percent)
    * @param {LegacyGasPriceKey} speed Preferred transaction speed, if uses legacy gas (before EIP-1559)
    * @param {number} bumpPercent Gas bump percent to prioritize transaction
-   * @returns {GasPrice} Estimated gas price info in WEI (hexed) - legacy object with gasPrice property or EIP-1559 object with maxFeePerGas
+   * @returns {Promise<GasPrice>} Estimated gas price info in WEI (hexed) - legacy object with gasPrice property or EIP-1559 object with maxFeePerGas
    *  and maxPriorityFeePerGas properties
    */
   async getGasPrice(
@@ -75,6 +75,22 @@ export abstract class TornadoFeeOracle implements ITornadoFeeOracle {
     }
   }
 
+  /**
+   * Estimate next block gas price
+   * @param {TxType} type Tornado transaction type (to select correct default bump percent)
+   * @param {LegacyGasPriceKey} speed Preferred transaction speed, if uses legacy gas (before EIP-1559)
+   * @param {number} bumpPercent Gas bump percent to prioritize transaction
+   * @returns {Promise<string>} Gas price in WEI (hex string)
+   */
+  async getGasPriceInHex(
+    type: TxType = 'other',
+    speed: LegacyGasPriceKey = 'fast',
+    bumpPercent: number = 0,
+  ): Promise<string> {
+    const gasPrice = await this.getGasPrice(type, speed, bumpPercent);
+    return calculateGasPriceInWei(gasPrice).toHexString();
+  }
+
   /**
    * Estimates gas limit for transaction (or basic gas limit, if no tx data provided)
    * @param {TransactionData} tx Transaction data (object in web3 / ethers format)

src/feeOracleV4.ts

@@ -17,12 +17,12 @@ export class TornadoFeeOracleV4 extends TornadoFeeOracle implements ITornadoFeeO
     super(chainId, rpcUrl, gasPriceOracle);
   }
 
-  async getGasLimit(tx?: TransactionData, type: TxType = 'other'): Promise<BigNumber> {
+  async getGasLimit(tx?: TransactionData, type: TxType = 'other', bumpPercent?: number): Promise<BigNumber> {
     if (type === 'user_withdrawal') return BigNumber.from(defaultWithdrawalGasLimit[this.chainId]);
 
     // Need to bump relayer gas limit for transaction, because predefined gas limit to small to be 100% sure that transaction will be sent
     // This leads to fact that relayer often pays extra for gas from his own funds, however, this was designed by previous developers
-    if (type === 'relayer_withdrawal') return bump(defaultWithdrawalGasLimit[this.chainId], 20);
+    if (type === 'relayer_withdrawal') return bump(defaultWithdrawalGasLimit[this.chainId], bumpPercent || 20);
     if (!tx) return BigNumber.from(21_000);
 
     return this.provider.estimateGas(tx);

src/types.ts

@@ -28,6 +28,7 @@ export interface TransactionData {
 export interface ITornadoFeeOracle {
   getGas: (tx?: TransactionData, type?: TxType) => Promise<BigNumber>;
   getGasPrice: (type?: TxType, speed?: LegacyGasPriceKey, bumpPercent?: number) => Promise<GasPrice>;
+  getGasPriceInHex: (type?: TxType, speed?: LegacyGasPriceKey, bumpPercent?: number) => Promise<string>;
   getGasLimit: (tx?: TransactionData, type?: TxType, bumpPercent?: number) => Promise<BigNumber>;
   calculateRefundInETH: () => Promise<BigNumber>;
   calculateWithdrawalFeeViaRelayer: (

src/utils.ts

@@ -15,7 +15,7 @@ export function serializeTx(tx?: TransactionData | string): string {
 
 export function calculateGasPriceInWei(gasPrice: GasPrice): BigNumber {
   // @ts-ignore
-  return gasPrice.gasPrice || gasPrice.maxFeePerGas;
+  return BigNumber.from(gasPrice.gasPrice || gasPrice.maxFeePerGas);
 }
 
 export function bump(value: BigNumberish, percent: number): BigNumber {