feat(entrykit): non-blocking fee estimation (#3784)

Author: alvrs

.changeset/four-zoos-smile.md

@@ -0,0 +1,5 @@
+---
+"@latticexyz/entrykit": patch
+---
+
+Fees for Redstone, Pyrope and Garnet are now cached for 10 seconds instead of fetched before every user operation.

packages/entrykit/src/actions/cachedFeesPerGas.ts

@@ -0,0 +1,26 @@
+import { Client, EstimateFeesPerGasReturnType } from "viem";
+import { estimateFeesPerGas } from "viem/actions";
+
+type CachedFeesPerGasOptions = {
+  refreshInterval?: number;
+};
+
+export function cachedFeesPerGas(
+  client: Client,
+  options: CachedFeesPerGasOptions = { refreshInterval: 10_000 },
+): () => Promise<EstimateFeesPerGasReturnType<"eip1559">> {
+  let fees: EstimateFeesPerGasReturnType<"eip1559"> | null = null;
+
+  async function refreshFees() {
+    fees = await estimateFeesPerGas(client);
+  }
+
+  refreshFees();
+  setInterval(refreshFees, options.refreshInterval);
+
+  return async () => {
+    if (fees) return fees;
+    fees = await estimateFeesPerGas(client);
+    return fees;
+  };
+}

packages/entrykit/src/createBundlerClient.ts

@@ -7,8 +7,7 @@ import {
 } from "viem/account-abstraction";
 import { defaultClientConfig } from "./common";
 import { getPaymaster } from "./getPaymaster";
-import { getAction } from "viem/utils";
-import { estimateFeesPerGas } from "viem/actions";
+import { cachedFeesPerGas } from "./actions/cachedFeesPerGas";
 
 export function createBundlerClient<
   transport extends Transport,
@@ -56,10 +55,9 @@ function createFeeEstimator(client: Client): undefined | (() => Promise<Estimate
   }
 
   // do our own fee calculation for redstone, garnet, pyrope chains
-  // because viem sets fees way too high by default
-  // https://github.com/wevm/viem/blob/253b1072ad9fe36a0e0491e173c85a6d69209ada/src/account-abstraction/actions/bundler/prepareUserOperation.ts#L436-L457
+  // to avoid the default RPC call to `eth_getBlockByNumber`
+  // https://github.com/wevm/viem/blob/3aa882692d2c4af3f5e9cc152099e07cde28e551/src/actions/public/estimateFeesPerGas.ts#L132
   if ([690, 17069, 695569].includes(client.chain.id)) {
-    // TODO: move to fee ref or similar approach
-    return () => getAction(client, estimateFeesPerGas, "estimateFeesPerGas")({ chain: client.chain });
+    return cachedFeesPerGas(client);
   }
 }

packages/entrykit/src/exports/internal.ts

@@ -11,6 +11,7 @@ export { AccountButton } from "../AccountButton";
 export { useAccountModal } from "../useAccountModal";
 export { useSessionClientReady as useSessionClient } from "../useSessionClientReady";
 export { createWagmiConfig, type CreateWagmiConfigOptions } from "../createWagmiConfig";
+export { withFeeCache } from "../utils/withFeeCache";
 
 // And some additional internal things
 export * from "../validateSigner";

packages/entrykit/src/getSessionClient.ts

@@ -44,7 +44,6 @@ export async function getSessionClient({
         publicClient: client,
       }),
     )
-
     // TODO: add observer once we conditionally fetch receipts while bridge is open
     .extend(() => ({ userAddress, worldAddress, internal_signer: sessionSigner }));
 

packages/entrykit/src/utils/withFeeCache.ts

@@ -0,0 +1,28 @@
+import { Chain, createClient, http } from "viem";
+import { cachedFeesPerGas } from "../actions/cachedFeesPerGas";
+
+type WithFeeCacheOptions = {
+  refreshInterval?: number;
+};
+
+export function withFeeCache<chain extends Chain>(
+  chain: chain,
+  options: WithFeeCacheOptions = { refreshInterval: 10_000 },
+): chain {
+  if (chain.fees?.estimateFeesPerGas) {
+    throw new Error("withFeeCache: estimateFeesPerGas already defined in chain config");
+  }
+
+  const client = createClient({
+    chain,
+    transport: http(),
+  });
+
+  return {
+    ...chain,
+    fees: {
+      ...chain.fees,
+      estimateFeesPerGas: cachedFeesPerGas(client, options),
+    },
+  };
+}