Merge pull request #426 from pimlicolabs/estimateErc20PaymasterCost

Add estimateErc20PaymasterCost

Author: plusminushalf

.changeset/swift-experts-act.md

@@ -0,0 +1,5 @@
+---
+"permissionless": patch
+---
+
+Added estimateErc20PaymasterCost

packages/permissionless/actions/pimlico/estimateErc20PaymasterCost.ts

@@ -0,0 +1,102 @@
+import {
+    type Account,
+    type Address,
+    type Chain,
+    ChainNotFoundError,
+    type Client,
+    type GetChainParameter,
+    type Transport
+} from "viem"
+import type { EntryPointVersion, UserOperation } from "viem/account-abstraction"
+import { getAction } from "viem/utils"
+import type { PimlicoRpcSchema } from "../../types/pimlico.js"
+import { getRequiredPrefund } from "../../utils/getRequiredPrefund.js"
+import { getTokenQuotes } from "./getTokenQuotes.js"
+
+/**
+ * @costInToken represents the max amount of token that will be charged for this user operation in token decimals
+ * @costInUsd represents the max amount of USD value of the token in 10^6 decimals
+ */
+export type EstimateErc20PaymasterCostReturnType = {
+    costInToken: bigint
+    costInUsd: bigint
+}
+
+export type EstimateErc20PaymasterCostParameters<
+    entryPointVersion extends EntryPointVersion,
+    TChain extends Chain | undefined,
+    TChainOverride extends Chain | undefined = Chain | undefined
+> = {
+    entryPoint: { version: entryPointVersion; address: Address }
+    userOperation: UserOperation<entryPointVersion>
+    token: Address
+} & GetChainParameter<TChain, TChainOverride>
+
+/**
+ * Returns all related fields to calculate the potential cost of a userOperation in ERC-20 tokens.
+ *
+ * - Docs: https://docs.pimlico.io/permissionless/reference/pimlico-bundler-actions/EstimateErc20PaymasterCost
+ *
+ * @param client that you created using viem's createClient whose transport url is pointing to the Pimlico's bundler.
+ * @returns quotes, see {@link EstimateErc20PaymasterCostReturnType}
+ *
+ */
+export const estimateErc20PaymasterCost = async <
+    entryPointVersion extends EntryPointVersion,
+    TChain extends Chain | undefined,
+    TChainOverride extends Chain | undefined = Chain | undefined
+>(
+    client: Client<
+        Transport,
+        TChain,
+        Account | undefined,
+        PimlicoRpcSchema<entryPointVersion>
+    >,
+    args: EstimateErc20PaymasterCostParameters<
+        entryPointVersion,
+        TChain,
+        TChainOverride
+    >
+): Promise<EstimateErc20PaymasterCostReturnType> => {
+    const chain = args.chain ?? client.chain
+
+    if (!chain) {
+        throw new ChainNotFoundError()
+    }
+
+    const { entryPoint, userOperation, token } = args
+
+    const quotes = await getAction(
+        client,
+        getTokenQuotes,
+        "getTokenQuotes"
+    )({
+        tokens: [token],
+        entryPointAddress: entryPoint.address,
+        chain
+    })
+
+    const postOpGas = quotes[0].postOpGas
+    const exchangeRate = quotes[0].exchangeRate
+    const exchangeRateNativeToUsd = quotes[0].exchangeRateNativeToUsd
+
+    const userOperationMaxCost = getRequiredPrefund({
+        userOperation,
+        entryPointVersion: entryPoint.version
+    })
+
+    // represents the userOperation's max cost in denomination of wei
+    const maxCostInWei =
+        userOperationMaxCost + postOpGas * userOperation.maxFeePerGas
+
+    // represents the userOperation's max cost in token denomination (wei)
+    const costInToken = (maxCostInWei * exchangeRate) / BigInt(1e18)
+
+    // represents the userOperation's max cost in usd (with 6 decimals of precision)
+    const costInUsd = (maxCostInWei * exchangeRateNativeToUsd) / 10n ** 18n
+
+    return {
+        costInToken,
+        costInUsd
+    }
+}

packages/permissionless/clients/decorators/pimlico.ts

@@ -10,6 +10,11 @@ import {
     sendCompressedUserOperation,
     validateSponsorshipPolicies
 } from "../../actions/pimlico.js"
+import {
+    type EstimateErc20PaymasterCostParameters,
+    type EstimateErc20PaymasterCostReturnType,
+    estimateErc20PaymasterCost
+} from "../../actions/pimlico/estimateErc20PaymasterCost.js"
 import {
     type GetUserOperationGasPriceReturnType,
     getUserOperationGasPrice
@@ -124,6 +129,18 @@ export type PimlicoActions<
             >
         >
     ) => Promise<Prettify<GetTokenQuotesReturnType>>
+    estimateErc20PaymasterCost: <
+        TChainOverride extends Chain | undefined = Chain | undefined
+    >(
+        args: Omit<
+            EstimateErc20PaymasterCostParameters<
+                entryPointVersion,
+                TChain,
+                TChainOverride
+            >,
+            "entryPoint"
+        >
+    ) => Promise<Prettify<EstimateErc20PaymasterCostReturnType>>
 }
 
 export const pimlicoActions =
@@ -162,5 +179,11 @@ export const pimlicoActions =
                 ...args,
                 chain: args.chain,
                 entryPointAddress: entryPoint.address
+            }),
+        estimateErc20PaymasterCost: async (args) =>
+            estimateErc20PaymasterCost(client, {
+                ...args,
+                entryPoint,
+                chain: args.chain
             })
     })