Builder

A UserOperation is a pseudo-transaction object used to execute actions through a smart contract account. Although it can be quite complex to create, the UserOperationBuilder simplifies this process using the builder pattern.

Interfaces

These interfaces are built using common ethers.js types. More specifically BigNumberish and BytesLike.

UserOperation

An interface for an ERC-4337 User Operation. Building a UserOperation involves constructing multiple parts and merging them together.

interface IUserOperation {
  sender: string;
  nonce: BigNumberish;
  initCode: BytesLike;
  callData: BytesLike;
  callGasLimit: BigNumberish;
  verificationGasLimit: BigNumberish;
  preVerificationGas: BigNumberish;
  maxFeePerGas: BigNumberish;
  maxPriorityFeePerGas: BigNumberish;
  paymasterAndData: BytesLike;
  signature: BytesLike;
}

UserOperationBuilder

An instance of UserOperationBuilder can help build a UserOperation that can be passed to the client.

const builder = new UserOperationBuilder();

interface IUserOperationBuilder {
  // get methods.
  getSender: () => string;
  getNonce: () => BigNumberish;
  getInitCode: () => BytesLike;
  getCallData: () => BytesLike;
  getCallGasLimit: () => BigNumberish;
  getVerificationGasLimit: () => BigNumberish;
  getPreVerificationGas: () => BigNumberish;
  getMaxFeePerGas: () => BigNumberish;
  getMaxPriorityFeePerGas: () => BigNumberish;
  getPaymasterAndData: () => BytesLike;
  getSignature: () => BytesLike;
  getOp: () => IUserOperation;

  // set methods.
  setSender: (address: string) => IUserOperationBuilder;
  setNonce: (nonce: BigNumberish) => IUserOperationBuilder;
  setInitCode: (code: BytesLike) => IUserOperationBuilder;
  setCallData: (data: BytesLike) => IUserOperationBuilder;
  setCallGasLimit: (gas: BigNumberish) => IUserOperationBuilder;
  setVerificationGasLimit: (gas: BigNumberish) => IUserOperationBuilder;
  setPreVerificationGas: (gas: BigNumberish) => IUserOperationBuilder;
  setMaxFeePerGas: (fee: BigNumberish) => IUserOperationBuilder;
  setMaxPriorityFeePerGas: (fee: BigNumberish) => IUserOperationBuilder;
  setPaymasterAndData: (data: BytesLike) => IUserOperationBuilder;
  setSignature: (bytes: BytesLike) => IUserOperationBuilder;
  setPartial: (partialOp: Partial<IUserOperation>) => IUserOperationBuilder;

  // Sets the default values that won't be wiped on reset.
  useDefaults: (partialOp: Partial<IUserOperation>) => IUserOperationBuilder;
  resetDefaults: () => IUserOperationBuilder;

  // Some fields may require arbitrary logic to build an op.
  // Middleware functions allow you to set custom logic for building op fragments.
  useMiddleware: (fn: UserOperationMiddlewareFn) => IUserOperationBuilder;
  resetMiddleware: () => IUserOperationBuilder;

  // This will construct a UserOperation that can be sent to a client.
  // It will run through your entire middleware stack in the process.
  buildOp: (
    entryPoint: string,
    chainId: BigNumberish
  ) => Promise<IUserOperation>;

  // Will reset all fields back to default value.
  resetOp: () => IUserOperationBuilder;
}

get and set Functions

These are basic getters and setters for all fields on a UserOperation. Getters return the field type whereas setters will return the instance to enable chaining.

For example:

const builder = new UserOperationBuilder()
  .setCallData(callData)
  .setCallGasLimit(callGas);