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Utility Methods

Utility methods handle approvals, allowances, refunds, and wallet authentication.

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allowance

Returns the current ERC-20 token allowance granted by a wallet to a spender contract. 
const result = await sdk.allowance(params: AllowanceRequestInterface): Promise<AllowanceResponseInterface>

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Parameters

FieldTypeDescription
blockchainBlockchainNameBlockchain where the token lives
tokenAddressstringERC-20 token contract address
walletAddressstringToken owner address
spenderAddressstringSpender contract address (e.g. Rubic router)

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Example

const result = await sdk.allowance({
    blockchain: 'ETH',
    tokenAddress: '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48', // USDC
    walletAddress: '0xYourWallet',
    spenderAddress: '0xRubicRouterAddress',
});

console.log('Allowance (wei):', result.allowance); // → '1000000000' (1000 USDC)

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checkApprove

Determines whether an ERC-20 approval is needed and, if so, returns the approval transaction data ready to send. 
const result = await sdk.checkApprove(params: ApproveRequestInterface): Promise<ApproveResponseInterface>

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Parameters

Extends AllowanceRequestInterface, plus:
FieldTypeDescription
blockchainBlockchainNameBlockchain where the token lives
tokenAddressstringERC-20 token address
walletAddressstringWallet that will approve
spenderAddressstringSpender to approve
amountstringToken amount to approve in token units (not wei)

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Response: ApproveResponseInterface

FieldTypeDescription
needApprovebooleanWhether an approval transaction is needed
transactionTransactionInterface | undefinedApproval tx data (present only if needApprove is true)
messagestringHuman-readable explanation

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Example

const approveInfo = await sdk.checkApprove({
    blockchain: 'ETH',
    tokenAddress: '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48', // USDC
    walletAddress: '0xYourWallet',
    spenderAddress: swapData.transaction.approvalAddress!,
    amount: '500', // 500 USDC
});

if (approveInfo.needApprove) {
    console.log('Approval needed:', approveInfo.message);

    // Send the approval transaction
    const approveTx = await signer.sendTransaction({
        to: approveInfo.transaction!.to,
        data: approveInfo.transaction!.data,
    });
    await approveTx.wait();

    console.log('Approved. Now proceed with the swap.');
} else {
    console.log('No approval needed:', approveInfo.message);
}
Tip: The approvalAddress field in the swap response contains the address to approve tokens for. Always use that value, as it may differ per provider.

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claim

Returns transaction data for claiming tokens that are ready to be redeemed via the Arbitrum Bridge (ETH ↔ Arbitrum). Used when waitForStatus resolves with status === 'READY_TO_CLAIM'. 
const tx = await sdk.claim(params: ClaimRequestInterface): Promise<TransactionInterface>

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Parameters

FieldTypeDescription
sourceTransactionHashstringThe source chain transaction hash
fromBlockchainEvmBlockchainNameSource blockchain: 'ETHEREUM' or 'ARBITRUM'

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Example

const status = await sdk.waitForStatus({ id: swapData.id, srcTxHash: tx.hash });

if (status.status === 'READY_TO_CLAIM') {
    const claimTx = await sdk.claim({
        sourceTransactionHash: tx.hash,
        fromBlockchain: 'ETHEREUM',
    });

    const claimResult = await signer.sendTransaction(claimTx);
    console.log('Claimed:', claimResult.hash);
}

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celerRefund

Returns transaction data for refunding a failed Celer Bridge cross-chain swap. 
const tx = await sdk.celerRefund(params: CelerRefundRequestInterface): Promise<TransactionInterface>

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Parameters

FieldTypeDescription
sourceTransactionHashstringThe source chain transaction hash
fromBlockchainCbridgeSupportedBlockchainSource blockchain

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Example

const refundTx = await sdk.celerRefund({
    sourceTransactionHash: '0xFailedTxHash',
    fromBlockchain: 'ETH',
});

await signer.sendTransaction(refundTx);

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authWalletMessage

Returns a message that the user must sign with their wallet for Retrobridge provider authentication. The resulting signature must be passed in the signature field of the swap request. 
const result = await sdk.authWalletMessage(walletAddress: string): Promise<AuthWalletResponseInterface>

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Example

const { messageToAuth } = await sdk.authWalletMessage('0xYourWallet');

// Sign the message with the user's wallet
const signature = await signer.signMessage(messageToAuth);

// Use the signature in the swap request
const swapData = await sdk.swap({
    // ... other params ...
    signature,
});

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healthcheck

Verifies the API is online. 
const result = await sdk.healthcheck(): Promise<string>
// → 'I am alive'
Useful for readiness checks before showing the UI: 
try {
    await sdk.healthcheck();
    // setApiAvailable(true);
} catch {
    // setApiAvailable(false);
    // showMaintenanceBanner();
}