@swapdk/wdk-protocol-bridge-swapdk-tron

WDK bridge protocol module for cross-chain swaps from TRON as source. Pairs with @swapdk/wdk-wallet-tron (a fork of @tetherto/wdk-wallet-tron that adds raw-calldata sendTransaction for arbitrary smart-contract calls) to route TRX / TRC-20 USDT → any destination supported by THORChain / MAYAChain via the SwapDK swap-engine.

How it works

WDK App
  └── SwapDKBridgeTron(tronAccount, config)
        ├── quoteBridge() → POST /quote (includeTx:false) → estimate
        └── bridge()      → POST /quote (includeTx:true) → POST /swap
                            └── TRC-20: account.sendTransaction({ approve calldata })
                                        ├─ wait for confirmation
                                        └─ account.sendTransaction({ depositWithExpiry calldata })
                                TRX:    account.sendTransaction({ depositWithExpiry calldata, callValue })

TRON inbound on THORChain uses the same router-contract pattern as EVM — THOR_router.depositWithExpiry(vault, asset, amount, memo, expiration) — just with base58 addresses and SUN as the value unit. swap-engine's TRON dispatch returns:

• tx.to — base58 router address (tronweb consumes directly)
• tx.data — full ABI-encoded calldata
• tx.value — callValue in SUN (decimal string) — populated for native TRX deposits, "0" for TRC-20
• tx.feeLimit — SUN cap on energy
• approvalTx — populated for TRC-20 sells (USDT/USDC approve)

The wallet receives these as sendTransaction({ to, value, data, feeLimit }) and emits a TriggerSmartContract with the raw calldata.

Chainflip TRON source is not supported in v1 — it uses a deposit-channel model (analogous to Chainflip BTC source) that the bridge module hasn't wired yet; Chainflip-only quotes are rejected upfront with a clear SwapDKUserError.

Install

npm install @swapdk/wdk-protocol-bridge-swapdk-tron \
            @swapdk/wdk-wallet-tron \
            @tetherto/wdk-wallet

Usage

import WalletManagerTron from '@swapdk/wdk-wallet-tron'
import { SwapDKBridgeTron } from '@swapdk/wdk-protocol-bridge-swapdk-tron'

const wallet = new WalletManagerTron('abandon abandon …', "0'/0/0", {
  provider: 'https://api.trongrid.io',
})
const account = await wallet.getAccount(0)

const bridge = new SwapDKBridgeTron(account, {
  apiUrl: 'https://api.swapdk.com',
  apiKey: process.env.SWAPDK_API_KEY!,
  slippageBps: 300,        // 3 %
})
bridge.setSourceChain('tron')

// Quote (free, doesn't broadcast)
const quote = await bridge.quoteBridge({
  amount: 100_000_000n,    // 100 TRX in SUN (TRX has 6 decimals)
  targetChain: 'ethereum',
  tokenOut: 'ETH.ETH',
  recipient: '0xRecipient…',
})

// Execute — native TRX path: single contract call to THORChain router
const result = await bridge.bridge({
  amount: 100_000_000n,
  targetChain: 'ethereum',
  tokenOut: 'ETH.ETH',
  recipient: '0xRecipient…',
})
// {
//   hash:           '<tron-txid>',
//   fee:            <SUN feeLimit cap>,
//   approveHash:    undefined,     // TRX path — no approval needed
//   bridgeFee:      <SUN>,
//   bridgeFeeAsset: 'TRON.TRX',
//   tokenInAmount:  100_000_000n,
//   tokenOutAmount: <wei>,
// }

// TRC-20 USDT path — bridge() emits an approve + depositWithExpiry pair
const usdtResult = await bridge.bridge({
  token: 'TRON.USDT-TR7NHqjeKQxGTCi8q8ZY4pL8otSzgjLj6t',
  amount: 10_000_000n,     // 10 USDT (6 decimals)
  targetChain: 'ethereum',
  tokenOut: 'ETH.ETH',
  recipient: '0xRecipient…',
})
// { ..., approveHash: '<tron-approve-txid>' }

// Track THORChain progress (poll until terminal)
await bridge.waitForBridge(result.hash, undefined, {
  pollIntervalMs: 15_000,
  timeoutMs: 600_000,
  onUpdate: (s) => console.log(s.status),
})

Configuration

| Field | Type | Default | Notes | |----------------|---------|----------|-------| | apiUrl | string | — | swap-engine base URL | | apiKey | string | — | sent as x-api-key | | slippageBps | number | 300 | basis points (300 = 3%) | | bridgeMaxFee | bigint | none | SUN — throws if liquidity fee exceeds the cap | | timeoutMs | number | 10_000 | HTTP request timeout | | retries | number | 2 | retries on network errors / 5xx |

Source token forms

The options.token field accepts:

• "native" / omitted → native TRX
• "TRX" → native TRX (shortcut)
• "TRON.TRX" → native TRX (SwapKit notation)
• "TRON.USDT-T…" → TRC-20 in SwapKit notation with base58 contract suffix

A bare base58 contract address ("T…") is not accepted — swap-engine's ConvertToChainflipFormat strips the address suffix and keeps the symbol; the symbol must be supplied verbatim.

Caveats

• Only THORChain / MAYAChain routes are supported in v1. Chainflip TRON source uses a deposit-channel inbound model that this module hasn't wired yet — Chainflip-only quotes throw a clear SwapDKUserError mentioning the provider. Adding Chainflip support is tracked separately.
• fee in the result is the SUN feeLimit cap committed to the contract call, not the actual energy burn. TRON's energy/bandwidth model makes pre-broadcast fee estimation impossible without a TronWeb roundtrip; we surface the cap as the conservative upper bound (matches the wallet's behaviour).
• TRC-20 paths always emit an approval tx. swap-engine doesn't currently check existing allowance on-chain before generating the approvalTx, so every TRC-20 swap pays a small approval fee (a few SUN of bandwidth). Allowance pre-check is a future server-side optimisation.
• Tracking returns null for the first ~30-60 seconds while THORChain waits for TRON confirmation (1-2 blocks). waitForBridge defaults to 15-second polling and a 10-minute timeout.

License

MIT