@thru/bridge

TypeScript SDK for Polygon-to-Thru bridge deposits and withdrawals.

Setup

import { createBridgeClient } from '@thru/bridge';

const bridge = createBridgeClient({
  polygon: {
    signer: {
      privateKey: process.env.POLYGON_PRIVATE_KEY!,
      rpcUrl: process.env.POLYGON_RPC_URL!,
    },
    polygonBridgeAddress: process.env.POLYGON_BRIDGE_ADDRESS!,
  },
  thru: {
    signer: {
      baseUrl: process.env.THRU_BASE_URL!,
      feePayerAddress: process.env.THRU_FEE_PAYER_ADDRESS!,
      feePayerPrivateKey: process.env.THRU_FEE_PAYER_PRIVATE_KEY!,
    },
    thruBridgeProgramAddress: process.env.THRU_BRIDGE_PROGRAM_ADDRESS!,
  },
});

Config is chain-scoped:

• polygon.polygonBridgeAddress: Polygon Bridge contract address.
• polygon.signer: Polygon transaction signer and fee payer.
• thru.thruBridgeProgramAddress: Thru bridge program address.
• thru.tokenProgramAddress: optional Token deployment override; defaults to the SDK's canonical taTOKENKRgcl3vO0yVhftATDbXuhgWcfaaxv9xpEEdMdUE for freshly bootstrapped networks. Set this explicitly for a different deployed network.
• thru.signer.feePayerAddress: Thru fee payer/depositor account (ta...).
• thru.signer.feePayerPrivateKey: Thru Ed25519 private key (32-byte hex).

Approve + Deposit Example

Approve first:

const approve = await bridge.approvePolygonToken({
  polygonTokenAddress: '0xYourPolygonTokenAddress',
  rawAmount: 1_000_000n,
});

Then deposit:

const result = await bridge.depositPolygonToThru({
  thruRecipient: 'taXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX',
  polygonTokenAddress: '0xYourPolygonTokenAddress',
  rawAmount: 1_000_000n,
});

console.log(result.polygonTxHash, result.polygonDepositEvent?.sequence.toString());

Metadata by token address:

const metadata = await bridge.getPolygonTokenMetadata('0xYourPolygonTokenAddress');
console.log(metadata.name, metadata.symbol, metadata.decimals);

Thru -> Polygon Example

Check if a Thru mint is actually a Polygon-bridged token:

const route = await bridge.getThruPolygonTokenRoute('taYourThruTokenMint');
if (!route.isPolygonBridgedToken) {
  throw new Error('mint is not bridged from Polygon');
}
console.log(route.polygonTokenAddress);

Deposit back to Polygon:

const result = await bridge.depositThruToPolygon({
  thruTokenMintAddress: 'taYourThruTokenMint',
  polygonRecipientAddress: '0xYourPolygonRecipient',
  rawAmount: 1_000_000n,
});

console.log(result.thruSignature);

Fixed Chain IDs

• thru = 1
• polygon = 2

Available Functions

Top-level exports:

• createBridgeClient(config)
• POLYGON_BRIDGE_ABI
• POLYGON_ERC20_ABI
• THRU_POLYGON_CHAIN_IDS
• THRU_TOKEN_PROGRAM_ADDRESS

BridgeClient methods:

• getPolygonTokenMetadata(polygonTokenAddress)
• approvePolygonToken({ polygonTokenAddress, rawAmount })
• depositPolygonToThru({ thruRecipient, polygonTokenAddress, rawAmount })
• getPolygonDepositFromTx(txHash)
• getThruPolygonTokenRoute(thruTokenMintAddress)
• depositThruToPolygon({ thruTokenMintAddress, polygonRecipientAddress, rawAmount, thruTokenAccountAddress?, payloadHex? })

Recipient address conversion is handled internally by depositPolygonToThru(...).

Amount Rules

• rawAmount is bigint only.
• rawAmount is validated as u64 (0..18446744073709551615).
• Submitted deposit amount must be > 0.

Allowance Requirement

• depositPolygonToThru(...) checks ERC20 allowance and throws if insufficient.
• Call approvePolygonToken(...) before deposit (or approve externally).