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getSwapOutput

Reads a computed swap result from the on-chain swap_outputs mapping.

Between the two phases of a private swap the chain computes the outcome and stores it here: amount_out and amount_remaining (both u128 bigint) are the values claimSwapOutput MUST be called with. Read them from chain — never from an off-chain service — because they gate money movement. Needs only a transport — no key, proving, or scanner. Hits the network for one node request via the client's transport.

null has two meanings the caller must distinguish by context: the request transaction has not finalized yet (retry), or the output was already claimed — a claim consumes the entry.

Usage​

import { createPublicClient, http } from '@provablehq/veil-core'
import { shieldSwapActions } from '@provablehq/shield-swap-sdk'

const client = createPublicClient({
  transport: http('https://api.provable.com/v2', { network: 'testnet' }),
}).extend(shieldSwapActions())

const out = await client.getSwapOutput({ swapId: handle.swapId! })
if (out) {
  const { amountOut } = await client.claimSwapOutput({ handle })
}
// { recipient: 'aleo1…', caller: 'aleo1…', token_in: '1223…field',
//   token_out: '4487…field', amount_out: 987654321000000000n,
//   amount_remaining: 0n, token_in_1: '0field', amount_remaining_1: 0n,
//   token_in_2: '0field', amount_remaining_2: 0n }

Returns​

Promise<SwapOutput | null>

The decoded swap output, or null when the swap id is not in the mapping — either not yet finalized, or already claimed.

  • recipient — string. Address the output records are issued to.
  • caller — string. Address that submitted the swap request.
  • token_in — string. Token id (field literal) sold.
  • token_out — string. Token id (field literal) bought.
  • amount_out — bigint. Raw atomic amount received (u128), as computed on chain.
  • amount_remaining — bigint. Raw atomic input refund (u128), non-zero when the swap partially filled at the price limit.
  • token_in_1 — string. Second input token id for a multi-hop swap leg; 0field when unused.
  • amount_remaining_1 — bigint. Refund for token_in_1 (u128).
  • token_in_2 — string. Third input token id for a multi-hop swap leg; 0field when unused.
  • amount_remaining_2 — bigint. Refund for token_in_2 (u128).

Parameters​

swapId​

  • Type: string

Swap id as an Aleo field literal, returned by swap as its first output, including the field suffix.

program​

  • Type: string
  • Default: shield_swap_v3.aleo

Program to read from.

Errors​

Throws a transport error when the node is unreachable or rejects the request, and a decode error when the value does not parse as a SwapOutput.