@tetherto/wdk-wallet-evm-erc-4337/src/wallet-manager-evm-erc-4337.js

A simple package to manage BIP-32 wallets for evm blockchains, which implement the erc-4337 standard and its account abstraction features

// Copyright 2024 Tether Operations Limited
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

'use strict'

import WalletManager from '@tetherto/wdk-wallet'

import WalletManagerEvm from '@tetherto/wdk-wallet-evm'

import { BrowserProvider, JsonRpcProvider } from 'ethers'

import WalletAccountEvmErc4337 from './wallet-account-evm-erc-4337.js'

/** @typedef {import('ethers').Provider} Provider */

/** @typedef {import('@tetherto/wdk-wallet-evm').FeeRates} FeeRates */

/** @typedef {import('./wallet-account-evm-erc-4337.js').EvmErc4337WalletConfig} EvmErc4337WalletConfig */

export default class WalletManagerEvmErc4337 extends WalletManager {
  /**
   * Creates a new wallet manager for evm blockchains that implements the [erc-4337](https://www.erc4337.io/docs) standard and its account abstraction features.
   *
   * @param {string | Uint8Array} seed - The wallet's [BIP-39](https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki) seed phrase.
   * @param {EvmErc4337WalletConfig} config - The configuration object.
   */
  constructor (seed, config) {
    super(seed, config)

    /**
     * The evm erc-4337 wallet configuration.
     *
     * @protected
     * @type {EvmErc4337WalletConfig}
     */
    this._config = config

    const { provider } = config

    if (provider) {
      /**
       * An ethers provider to interact with a node of the blockchain.
       *
       * @protected
       * @type {Provider | undefined}
       */
      this._provider = typeof provider === 'string'
        ? new JsonRpcProvider(provider)
        : new BrowserProvider(provider)
    }
  }

  /**
   * Returns the wallet account at a specific index (see [BIP-44](https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki)).
   *
   * @example
   * // Returns the account with derivation path m/44'/60'/0'/0/1
   * const account = await wallet.getAccount(1);
   * @param {number} [index] - The index of the account to get (default: 0).
   * @returns {Promise<WalletAccountEvmErc4337>} The account.
   */
  async getAccount (index = 0) {
    return await this.getAccountByPath(`0'/0/${index}`)
  }

  /**
   * Returns the wallet account at a specific BIP-44 derivation path.
   *
   * @example
   * // Returns the account with derivation path m/44'/60'/0'/0/1
   * const account = await wallet.getAccountByPath("0'/0/1");
   * @param {string} path - The derivation path (e.g. "0'/0/0").
   * @returns {Promise<WalletAccountEvmErc4337>} The account.
   */
  async getAccountByPath (path) {
    if (!this._accounts[path]) {
      const account = new WalletAccountEvmErc4337(this.seed, path, this._config)

      this._accounts[path] = account
    }

    return this._accounts[path]
  }

  /**
   * Returns the current fee rates.
   *
   * @returns {Promise<FeeRates>} The fee rates (in weis).
   */
  async getFeeRates () {
    if (!this._provider) {
      throw new Error('The wallet must be connected to a provider to get fee rates.')
    }

    const { maxFeePerGas } = await this._provider.getFeeData()

    return {
      normal: maxFeePerGas * WalletManagerEvm._FEE_RATE_NORMAL_MULTIPLIER / 100n,
      fast: maxFeePerGas * WalletManagerEvm._FEE_RATE_FAST_MULTIPLIER / 100n
    }
  }
}