@delvtech/drift

Drift

Effortless Ethereum Development Across Web3 Libraries

Write cached Ethereum smart contract interactions once with Drift and run them anywhere. Seamlessly support multiple web3 libraries like viem, web3.js, and ethers—without getting locked into a single provider or rewriting code.

With built-in caching, type-safe contract APIs, and easy-to-use testing mocks, Drift lets you build efficient and reliable applications without worrying about call optimizations or juggling countless hooks. Focus on what matters: creating great features and user experiences.

Why Drift?

Building on Ethereum often means dealing with:

• Optimizing Network Calls: Manually caching calls and optimizing queries to minimize RPC requests slows down development.
• Managing Multiple Hooks: Each contract call often needs its own hook and query key to prevent redundant network requests.
• Complex Testing: Setting up mocks for contract interactions can be cumbersome and error-prone.
• Hard Dependency on a Specific Web3 Library: There are several competing options, like viem, web3.js, ethers.js. Tying your business logic to a specific one creates vendor lock-in and makes it harder to switch down the road.

Drift Solves These Problems

• ⚡ Optimized Performance: Automatically reduces redundant RPC calls with built-in caching. No need to manage hooks or query keys for each call.
• 🔒 Type Safety: Drift's type-checked APIs help catch errors at compile time.
• 🧪 Testing Made Easy: Built-in mocks simplify testing your contract interactions. Drift's testing mocks are also type-safe, ensuring your tests are always in sync with your contracts.
• 🌐 Multi-Library Support: Drift provides a unified interface compatible with multiple web3 libraries. Write your contract logic once and use it across different providers.
• 🔄 Extensibility: Designed to grow with your project's needs, Drift allows you to easily extend support to new web3 libraries by creating small adapter packages.

Table of Contents

• Installation
• Start Drifting
  • 1. Create a Drift client
  • 2. Interact with your Contracts
    • Read Operations with Caching
    • Write Operations
    • Deployments
    • Contract Instances
• Example: Building Vault Clients
  • 1. Define vault clients
  • 2. Use the clients in your application
    • Benefits of This Architecture
  • 3. Test Your Clients with Drift's Built-in Mocks
    • Example: Testing Client Methods with Multiple RPC Calls
    • Benefits
• Simplifying React Hook Management
  • The Problem Without Drift
  • How Drift Helps
    • Example Using React Query
• Caching in Action
  • Cache Invalidation
  • Preloading Cache Data
  • Direct Access to Cached Data
• Extending Drift for Your Needs
  • Extension Points
    • Adapters
    • Stores
  • Hooks
• Contributing
• License

Installation

Install Drift:

npm install @delvtech/drift

Optional: To use Drift with a specific web3 library, install the corresponding adapter:

# Install one (optional)
npm install @delvtech/drift-viem
npm install @delvtech/drift-web3
npm install @delvtech/drift-ethers
npm install @delvtech/drift-ethers-v5

[!TIP]

Drift can be used without an adapter, however adapters reuse clients from their corresponding web3 library, which can improve performance depending on their configuration. For example, the publicClient from Viem can automatically batch requests via MultiCall.

Start Drifting

1. Create a Drift client

import { createDrift } from "@delvtech/drift";

const drift = createDrift({
  rpcUrl: "[YOUR_RPC_URL]",
});

Viem adapter example:

import { createDrift } from "@delvtech/drift";
import { viemAdapter } from "@delvtech/drift-viem";
import { createPublicClient, createWalletClient, http } from "viem";

const publicClient = createPublicClient({
  transport: http(),
});

// optionally create a wallet client
const walletClient = createWalletClient({
  transport: http(),
});

const drift = createDrift({
  adapter: viemAdapter({ publicClient, walletClient }),
});

2. Interact with your Contracts

Read Operations with Caching

import { VaultAbi } from "./abis/VaultAbi";

// No need to wrap in separate hooks; Drift handles caching internally
const balance = await drift.read({
  abi: VaultAbi,
  address: "0xYourVaultAddress",
  fn: "balanceOf",
  args: {
    account: "0xUserAddress",
  },
});

Write Operations

If Drift was initialized with a signer, you can perform write operations:

const txHash = await drift.write({
  abi: VaultAbi,
  address: "0xYourVaultAddress",
  fn: "deposit",
  args: {
    amount: BigInt(100e18),
    receiver: "0xReceiverAddress",
  },

  // Optionally wait for the transaction to be mined and invalidate cache
  onMined: () => {
    drift.cache.invalidateRead({
      abi: VaultAbi,
      address: "0xYourVaultAddress",
      fn: "balanceOf",
      args: {
        account: "0xReceiverAddress",
      },
    });
  },
});

Deployments

const txHash = await drift.deploy({
  abi: ERC20.abi,
  bytecode: ERC20.bytecode,
  args: {
    decimals_: 18,
    initialSupply: 100_000_000n * 10n ** 18n, // 100M
  },
});

// Wait for the receipt to get the contract address
const receipt = await drift.waitForTransaction({ hash: txHash });

if (receipt?.status === "success" && receipt?.contractAddress) {
  const totalSupply = await drift.read({
    abi: ERC20.abi,
    address: receipt.contractAddress,
    fn: "totalSupply",
  });
  // => 100000000000000000000000000n
}

Contract Instances

Create contract instances to write your options once and get a streamlined, type-safe API to re-use across your application.

const vault = drift.contract({
  abi: VaultAbi,
  address: "0xYourVaultAddress",
  // ...other options
});

const balance = await vault.read("balanceOf", { account });

const txHash = await vault.write(
  "deposit",
  {
    amount: BigInt(100e18),
    receiver: "0xReceiverAddress",
  },
  {
    onMined: () => {
      vault.cache.invalidateRead("balanceOf", { account: "0xReceiverAddress" });
    },
  },
);

Example: Building Vault Clients

Let's build a simple library agnostic SDK with ReadVault and ReadWriteVault clients using Drift.

1. Define vault clients

In your core SDK package, define the ReadVault and ReadWriteVault clients using Drift's ReadContract and ReadWriteContract abstractions.

// sdk-core/src/VaultClient.ts
import {
  type Address,
  type Drift,
  type EventLog,
  type Hash,
  type ReadContract,
  type ReadWriteAdapter,
  type ReadWriteContract,
  createDrift,
} from "@delvtech/drift";
import { erc4626Abi } from "./abis/Erc4626";

type VaultAbi = typeof erc4626Abi;

/** A Read-Only Vault client */
export class ReadVault {
  contract: ReadContract<VaultAbi>;
  
  constructor(address: Address, drift: Drift = createDrift()) {
    this.contract = drift.contract({
      abi: erc4626Abi,
      address,
    });
  }

  // Make read calls with internal caching
  getBalance(account: Address): Promise<bigint> {
    return this.contract.read("balanceOf", { account });
  }
  getDecimals(): Promise<number> {
    return this.contract.read("decimals");
  }

  // Fetch events with internal caching
  getDeposits(account?: Address): Promise<EventLog<VaultAbi, "Deposit">[]> {
    return this.contract.getEvents("Deposit", {
      filter: {
        sender: account,
      },
    });
  }
}

export class ReadWriteVault extends ReadVault {
  declare contract: ReadWriteContract<VaultAbi>;

  constructor(
    address: Address,
    drift: Drift<ReadWriteAdapter> = createDrift(),
  ) {
    super(address, drift);
  }

  // Make a deposit
  deposit(amount: bigint, account: Address): Promise<Hash> {
    return this.contract.write(
      "deposit",
      {
        assets: amount,
        receiver: account,
      },
      {
        // Optionally wait for the transaction to be mined and invalidate cache
        onMined: (receipt) => {
          if (receipt?.status === "success") {
            this.contract.cache.invalidateRead("balanceOf", { account });
          }
        },
      },
    );
  }
}

2. Use the clients in your application

Using an adapter, you can integrate Drift with your chosen web3 library. Here's an example using viem:

import { createDrift } from "@delvtech/drift";
import { viemAdapter } from "@delvtech/drift-viem";
import { createPublicClient, http } from "viem";
import { ReadVault } from "sdk-core";

const publicClient = createPublicClient({
  transport: http(),
  // ...other options
});

const drift = createDrift({
  adapter: viemAdapter({ publicClient }),
});

// Instantiate the ReadVault client
const readVault = new ReadVault("0xYourVaultAddress", drift);

// Fetch user balance
const userBalance = await readVault.getBalance("0xUserAddress");

// Get deposit history
const deposits = await readVault.getDeposits("0xUserAddress");

Benefits of This Architecture

• Reusability: Write your business logic once and reuse it across different environments. Easily extend support to new web3 libraries by creating small adapter packages.
• Simplicity: Your application code stays clean and focused on business logic rather than on optimizing network calls or managing cache keys.

3. Test Your Clients with Drift's Built-in Mocks

Testing smart contract interactions can be complex and time-consuming. Drift simplifies this process by providing built-in mocks that allow you to stub responses and focus on testing your application logic.

[!IMPORTANT]

Drift's testing mocks have a peer dependency on Sinon.JS. Make sure to install it before using the mocks.

npm install --save-dev sinon

Example: Testing Client Methods with Multiple RPC Calls

Suppose you have a method, getAccountValue, in your ReadVault client that gets the total asset value for an account by fetching their vault balance and converting it to assets. Under the hood, this method makes multiple RPC requests.

Here's how you can use Drift's mocks to stub contract calls and test your method:

// sdk-core/src/ReadVault.test.ts
import { createMockDrift } from "@delvtech/drift/testing";
import { vaultAbi } from "./abis/VaultAbi";
import { ReadVault } from "./VaultClient";

test("getUserAssetValue should return the total asset value for a user", async () => {
  // Set up mocks
  const mockDrift = createMockDrift();
  const mockContract = mockDrift.contract({
    abi: vaultAbi,
    address: "0xVaultAddress",
  });

  // Stub the vault's return values using `on*` methods
  mockContract.onRead("balanceOf", { account: "0xUserAddress" }).resolves(
    BigInt(100e18), // User has 100 vault shares
  );
  mockContract.onRead("convertToAssets", { shares: BigInt(100e18) }).resolves(
    BigInt(150e18), // 100 vault shares are worth 150 in assets
  );

  // Instantiate your client with the mocked Drift instance
  const readVault = new ReadVault("0xVaultAddress", mockDrift);

  // Call the method you want to test
  const accountAssetValue = await readVault.getAccountValue("0xUserAddress");

  // Assert the expected result
  expect(accountAssetValue).toEqual(BigInt(150e18));
});

Benefits

• No Network Calls: Tests run faster and more reliably without actual network interactions.
• Focus on Logic: Concentrate on testing your application's business logic.
• Easy Setup: Minimal configuration required to get started with testing.

Simplifying React Hook Management

The Problem Without Drift

In traditional setups, you might rely on data-fetching libraries like React Query. However, to prevent redundant network requests, each contract call would need:

• Its own hook (e.g., useBalanceOf, useTokenSymbol).
• Unique query keys for caching.

Composing multiple calls becomes cumbersome, as you have to manage each hook's result separately.

How Drift Helps

Drift's internal caching means you don't need to wrap every contract call in a separate hook. You can perform multiple contract interactions within a single function or hook without worrying about redundant requests.

Example Using React Query

import { useQuery } from "@tanstack/react-query";
import { ReadVault } from "sdk-core";

function useVaultData(readVault: ReadVault, userAddress: string) {
  return useQuery(["vaultData", userAddress], async () => {
    // Perform multiple reads without separate hooks or query keys
    const [balance, symbol, deposits] = await Promise.all([
      readVault.getBalance(userAddress),
      readVault.contract.read("symbol"),
      readVault.getDeposits(userAddress),
    ]);

    return { balance, symbol, deposits };
  });
}

No need to manage multiple hooks or query keys — Drift handles caching internally, simplifying your code and development process.

Caching in Action

Drift's caching mechanism ensures that repeated calls with the same parameters don't result in unnecessary network requests, even when composed within the same function.

// Both calls use the cache; only one network request is made
const balance1 = await contract.read("balanceOf", { account });
const balance2 = await contract.read("balanceOf", { account });

Cache Invalidation

Delete cached data to ensure it's re-fetched using invalidate* and clear* methods.

// Invalidate the cache for a specific read
contract.cache.invalidateRead("balanceOf", { account });

// Invalidate all reads matching partial arguments
contract.cache.invalidateReadsMatching("balanceOf");

// Invalidate all reads associated with the contract
contract.cache.clearReads();

// Let it all go...
contract.cache.clear();

Preloading Cache Data

Add static data such as immutables from token lists using preload* methods to avoid network requests without changing how the data is accessed.

const drift = createDrift(/* ... */);
const contract = drift.contract({
  abi: erc20Abi,
  // ...
});

// Preloading read data
contract.cache.preloadRead({ fn: "symbol", value: "DAI" });

// Preloading event data
contract.cache.preloadEvents({
  event: "Transfer",
  value: [],
  // ...
});

Direct Access to Cached Data

Drift clients will automatically check the cache before fetching new data, but direct access to the cached data is available via get* methods.

// Get a cached read return
const cachedBalance = await contract.cache.getRead("balanceOf", { account });

// Get a cached transaction receipt
const cachedReceipt = await drift.cache.getTransactionReceipt({ hash })

The invalidate*, clear*, preload*, and get* methods are available on both the Drift.cache and Contract.cache instances.

[!IMPORTANT]

Manipulating cache data affects all clients that share the same cache. Since Drift passes its own cache to the contracts it creates via Drift.contract(), they'll already be preloaded with the Drift instance's cache and any cache operations performed on the contract cache will also affect the Drift cache.

Extending Drift for Your Needs

Drift is designed to be extensible. You can build additional abstractions or utilities on top of it to suit your project's requirements.

Extension Points

Adapters

Extend support to new web3 libraries or custom providers by implementing the Adapter interface. Drift Clients, including Drift, extend the prototype of the Adapter they're provided, inheriting all of it's properties and methods, extending some, and adding some of their own. See the DefaultAdapter for an example implementation.

import { DefaultAdapter, createDrift } from "@delvtech/drift";

class CustomAdapter extends DefaultAdapter {
  override async getChainId(): Promise<number> {
    // Custom implementation...
  }
}

const drift = await createDrift({
  adapter: new CustomAdapter({
    rpcUrl: process.env.RPC_URL,
  }),
});

Stores

Implement a custom Store to manage caching in a way that suits your application. The default store is an in-memory LRU cache, but you can create a custom store that uses TTL, localStorage, IndexedDB, QueryClient, or any other storage mechanism, sync or async.

import { createDrift } from "@delvtech/drift";

const drift = createDrift({
  store: new Map<string, unknown>(),
});

Hooks

Add custom logic by intercepting and modifying client methods with hooks. Each client method (including custom adapter methods) has type-safe before:<method> and after:<method> hooks that can be used to inspect and modify the arguments or results.

// Simulate writes before sending transactions
drift.hooks.on("before:write", async ({ args: [params] }) => {
  await drift.simulateWrite(params);
});

// Run middleware on reads
drift.hooks.on("before:read", async ({ args: [params], resolve }) => {
  const cachedValue = await drift.cache.getRead(params);
  resolve(readMiddleware({ drift, params, cachedValue }));
});

// Run middleware to transform the result of calls
drift.hooks.on("after:call", ({ args: [params], result, setResult }) => {
  const transformedResult = callResultMiddleware({ drift, params, result });
  setResult(transformedResult);
});

Contributing

Got ideas or found a bug? Check the Contributing Guide to get started.

License

Drift is open-source software licensed under the Apache 2.0.