@alchemy/aa-core/src/middleware/actions.ts

viem based SDK that enables interactions with ERC-4337 Smart Accounts. ABIs are based off the definitions generated in @account-abstraction/contracts

import {
  isHex,
  type Chain,
  type Client,
  type PublicActions,
  type PublicRpcSchema,
  type Transport,
} from "viem";
import type { SmartContractAccount } from "../account/smartContractAccount.js";
import type {
  BundlerActions,
  BundlerRpcSchema,
} from "../client/decorators/bundlerClient.js";
import type { ClientMiddlewareConfig } from "../client/types.js";
import {
  concatPaymasterAndData,
  parsePaymasterAndData,
} from "../utils/userop.js";
import { defaultFeeEstimator } from "./defaults/feeEstimator.js";
import { defaultGasEstimator } from "./defaults/gasEstimator.js";
import { defaultPaymasterAndData } from "./defaults/paymasterAndData.js";
import { defaultUserOpSigner } from "./defaults/userOpSigner.js";
import { noopMiddleware } from "./noopMiddleware.js";
import type { ClientMiddleware } from "./types.js";

/**
 * Middleware client type
 *
 * @template {Transport} TTransport
 * @template {Chain | undefined} TChain
 * @template {SmartContractAccount | undefined} TAccount
 */
export type MiddlewareClient<
  TTransport extends Transport = Transport,
  TChain extends Chain | undefined = Chain | undefined,
  TAccount extends SmartContractAccount | undefined =
    | SmartContractAccount
    | undefined
> = Client<
  TTransport,
  TChain,
  TAccount,
  [...BundlerRpcSchema, ...PublicRpcSchema],
  PublicActions & BundlerActions
>;

/**
 * export function that takes in {@link ClientMiddlewareConfig} used during client initiation
 * and returns the middleware actions object that the smart account client extends with
 *
 * @param overrides - {@link ClientMiddlewareConfig} used during client initiation for overriding default middlewares
 * @returns middleware actions object
 */
export const middlewareActions =
  (overrides: ClientMiddlewareConfig) =>
  <
    TTransport extends Transport = Transport,
    TChain extends Chain | undefined = Chain | undefined,
    TAccount extends SmartContractAccount | undefined =
      | SmartContractAccount
      | undefined
  >(
    client: MiddlewareClient<TTransport, TChain, TAccount>
  ): { middleware: ClientMiddleware } => ({
    middleware: {
      customMiddleware: overrides.customMiddleware ?? noopMiddleware,
      dummyPaymasterAndData: overrides.paymasterAndData?.dummyPaymasterAndData
        ? async (struct, { account }) => {
            const data = overrides.paymasterAndData!.dummyPaymasterAndData();
            const paymasterOverrides =
              account.getEntryPoint().version === "0.7.0"
                ? isHex(data)
                  ? parsePaymasterAndData(data)
                  : data
                : {
                    paymasterAndData: isHex(data)
                      ? data
                      : concatPaymasterAndData(data),
                  };
            return { ...struct, ...paymasterOverrides };
          }
        : defaultPaymasterAndData,

      feeEstimator: overrides.feeEstimator ?? defaultFeeEstimator(client),
      gasEstimator: overrides.gasEstimator ?? defaultGasEstimator(client),
      paymasterAndData:
        overrides.paymasterAndData?.paymasterAndData ?? defaultPaymasterAndData,
      userOperationSimulator:
        overrides.userOperationSimulator ?? noopMiddleware,
      signUserOperation: overrides.signUserOperation ?? defaultUserOpSigner,
    },
  });