@avalabs/bridge-unified

A package for routing tokens from Chain A to Chain B, and unifying multiple bridge tools into one.

What is this?

The bridging ecosystem is complex. There are often multiple tools that can be used to bridge tokens from one chain to another, and sometimes to get a token from chain A to C you need to use multiple bridging tools and route through chain B first. This package simplifies that process by creating the Unified Bridge API, a standard interface for bridging tokens from one chain to another without having to worry about the underlying tools or the underlying intermediary chains.

These are the bridges we currently support:

• CCTP - preferred for brdiging USDC between Ethereum and Avalanche C-Chain. See the bridges/cctp folder.

Future bridges we plan to support:

• Avalanche Bridge - is capable of transferring a fixed list of tokens between Ethereum and Avalanche C-Chain.
• Teleporter - for moving tokens between subnets.
• Cross-Chain Transfer - for moving tokens between the three Avalanche Primary Network chains (X-Chain, C-Chain, and P-Chain).

Getting Started

  npm install @avalabs/bridge-unified
  # or
  yarn add @avalabs/bridge-unified
  # or
  pnpm add @avalabs/bridge-unified

Initialization

import { createUnifiedBridgeService, Environment, BridgeTransfer } from '@avalabs/bridge-unified';

// create a new service for an environment
const unifiedService = createUnifiedBridgeService({
  environment: Environment.TEST,
});

// init the service, fetch and setup its configs
await unifiedService.init();

// get the list of supported assets, grouped by chain IDs
const assets = await unifiedService.getAssets()

// get the bridge fee(s) of the provided transfer
const fees = await unifiedService.getFees({...})

// start a new bridge transfer and store its state
const bridgeTransfer = await unifiedService.transferAsset({...})

// create an update listener for tracking
const updateListener = (transfer: BridgeTransfer) => {
  console.log(transfer)
}

// start tracking the transfer's state. whenever the state changes, it will call the provided `updateListener`
const { cancel, result } = await unifiedService.trackTransfer({bridgeTransfer, updateListener, ...})

// immediatelly stops tracking and rejects the tracker's promise
// cancel()

// wait for the transfer to finish and get its final state
const finalizedBridgeTransfer = await result

API

createUnifiedBridgeService({ environment, disabledBridgeTypes? })

Returns a new unifiedBridgeService for the given environment, using all supported bridge integrations by default. Individual bridges can be turned off via the disabledBridgeTypes array.

environment

Type: Environment

Defines if the bridge service should use testnet or mainnet.

disabledBridgeTypes

Type: BridgeType[] | undefined

Disables the integration of the provided BridgeTypes.

unifiedBridgeService

Contains all the required properties and methods to prepare, initiate or track a bridge transfer. Automatically picks the right (enabled) bridge integration to use based on the provided params.

{
  environment, // the provided Environment during initialization
  bridges, // the list of enabled bridge integrations
  init,
  updateConfigs,
  getAssets,
  getFees,
  transferAsset,
  trackTransfer,
}

init

Type: () => Promise<void>

Initializes the unified service by attempting to fetch the configurations of the enabled bridges.

updateConfigs

Type: () => Promise<void>

Attempts to fetch the configurations of the enabled bridges.

getAssets

Type: () => Promise<ChainAssetMap>

Returns the aggregated list of assets supported by the enabled bridges grouped by chain IDs.

getFees

Type: (params: FeeParams) => Promise<AssetFeeMap>

Calculates and returns the bridge fees in tokenAddress - amount pairs for a given bridge transfer.

transferAsset

Type: (params: TransferParams) => Promise<BridgeTransfer>

Starts a new bridge transfer, executing every required step in a single call. Transactions signing is done by either the provided sourceProvider or a custom sign callback. Returns a BridgeTransfer containing all the (known) initial values such as: environment, addresses, amount, fee, transaction hash, required and actual block confirmation counts, etc.

trackTransfer

Type: (params: TrackingParams) => ({cancel, result})

Tracks the given BridgeTransfer's progress and invokes the provided listener callback whenever a change happens.

cancel

Type: () => void

If it's still pending, rejects the tracker's promise (result) immediatelly and breaks its loop under the hood.

result

Type: Promise<BridgeTransfer>

Resolves with the finalized BridgeTransfer (if not canceled before).