import/export hackery

src/gasPriceOracle/adapters/arbitrum.ts

@@ -1,14 +1,15 @@
 import { providers } from "ethers";
-import { bnOne, parseUnits } from "../../utils";
+import { BigNumber, bnOne, parseUnits } from "../../utils";
 import { GasPriceEstimate } from "../types";
 import * as ethereum from "./ethereum";
 
-const DEFAULT_PRIORITY_FEE = parseUnits("1.5", 9);
+let DEFAULT_PRIORITY_FEE: BigNumber | undefined = undefined;
 
 // Arbitrum Nitro implements EIP-1559 pricing, but the priority fee is always refunded to the caller. Further,
 // ethers typically hardcodes the priority fee to 1.5 Gwei. So, confirm that the priority fee supplied was 1.5
 // Gwei, and then drop it to 1 Wei. Reference: https://developer.arbitrum.io/faqs/gas-faqs#q-priority
 export async function eip1559(provider: providers.Provider, chainId: number): Promise<GasPriceEstimate> {
+  DEFAULT_PRIORITY_FEE ??= parseUnits("1.5", 9);
   const { maxFeePerGas: _maxFeePerGas, maxPriorityFeePerGas } = await ethereum.eip1559(provider, chainId);
 
   // If this throws, ethers default behaviour has changed, or Arbitrum RPCs are returning something more sensible.

src/utils/BigNumberUtils.ts

@@ -5,12 +5,10 @@
  */
 
 import { utils as ethersUtils } from "ethers";
-import * as ethersBigNumber from "@ethersproject/bignumber";
+import { BigNumber, BigNumberish } from "@ethersproject/bignumber";
 
-export const { BigNumber } = ethersBigNumber;
-export type BigNumberish = ethersBigNumber.BigNumberish;
-export type BigNumber = ethersBigNumber.BigNumber;
-export type BN = ethersBigNumber.BigNumber;
+export * from "@ethersproject/bignumber";
+export type BN = BigNumber;
 
 export const { formatEther, formatUnits, parseEther, parseUnits } = ethersUtils;
 export const bnZero = BigNumber.from("0");