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Creates a Hash Time-Locked Contract (HTLC) for atomic swaps and conditional payments.

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Method Signature

async createHTLC({
  receiverSparkAddress,
  amountSats,
  preimage,
  expiryTime,
}: {
  receiverSparkAddress: string;
  amountSats: number;
  preimage?: string;  // Optional - auto-generated if not provided
  expiryTime: Date;
}): Promise<Transfer>

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Parameters

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receiverSparkAddress
string
required
The Spark address of the receiver
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amountSats
number
required
The amount in satoshis to lock
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preimage
string
The preimage (32 bytes hex) for the HTLC hash lock. If not provided, a deterministic preimage is generated using getHTLCPreimage().
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expiryTime
Date
required
The expiry time for the HTLC (must be in the future)

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Returns

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transfer
Transfer
required
The HTLC transfer details

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Example

// With auto-generated preimage (recommended)
const htlc = await wallet.createHTLC({
  receiverSparkAddress: "spark1...",
  amountSats: 10000,
  expiryTime: new Date(Date.now() + 3600000) // 1 hour from now
});
console.log("HTLC created:", htlc.id);

// With custom preimage
const htlcWithPreimage = await wallet.createHTLC({
  receiverSparkAddress: "spark1...",
  amountSats: 10000,
  preimage: "abc123def456...", // 32 bytes hex
  expiryTime: new Date(Date.now() + 3600000)
});