feat(wasm-utxo)!: return transaction object from extractTransaction

Changes extractTransaction() to return a Transaction object instead of raw
bytes. The transaction object provides additional functionality like getId()
to get the transaction ID directly.

This is a breaking change as the return type changes from Uint8Array to a
Transaction object. Clients need to call toBytes() on the returned object
to get the raw bytes.

Issue: BTC-2978

Co-authored-by: llm-git <llm-git@ttll.de>

Author: OttoAllmendinger

packages/wasm-utxo/js/fixedScriptWallet/BitGoPsbt.ts

@@ -6,6 +6,12 @@ import { type ECPairArg, ECPair } from "../ecpair.js";
 import type { UtxolibName } from "../utxolibCompat.js";
 import type { CoinName } from "../coinName.js";
 import type { InputScriptType } from "./scriptType.js";
+import {
+  Transaction,
+  DashTransaction,
+  ZcashTransaction,
+  type ITransaction,
+} from "../transaction.js";
 
 export type { InputScriptType };
 
@@ -755,11 +761,19 @@ export class BitGoPsbt {
   /**
    * Extract the final transaction from a finalized PSBT
    *
-   * @returns The serialized transaction bytes
+   * @returns The extracted transaction instance
    * @throws Error if the PSBT is not fully finalized or extraction fails
    */
-  extractTransaction(): Uint8Array {
-    return this._wasm.extract_transaction();
+  extractTransaction(): ITransaction {
+    const networkType = this._wasm.get_network_type();
+
+    if (networkType === "dash") {
+      return DashTransaction.fromWasm(this._wasm.extract_dash_transaction());
+    }
+    if (networkType === "zcash") {
+      return ZcashTransaction.fromWasm(this._wasm.extract_zcash_transaction());
+    }
+    return Transaction.fromWasm(this._wasm.extract_bitcoin_transaction());
   }
 
   /**

packages/wasm-utxo/js/fixedScriptWallet/ZcashBitGoPsbt.ts

@@ -1,6 +1,7 @@
 import { BitGoPsbt as WasmBitGoPsbt } from "../wasm/wasm_utxo.js";
 import { type WalletKeysArg, RootWalletKeys } from "./RootWalletKeys.js";
 import { BitGoPsbt, type CreateEmptyOptions } from "./BitGoPsbt.js";
+import { ZcashTransaction } from "../transaction.js";
 
 /** Zcash network names */
 export type ZcashNetworkName = "zcash" | "zcashTest" | "zec" | "tzec";
@@ -160,4 +161,14 @@ export class ZcashBitGoPsbt extends BitGoPsbt {
   get expiryHeight(): number {
     return this.wasm.expiry_height();
   }
+
+  /**
+   * Extract the final Zcash transaction from a finalized PSBT
+   *
+   * @returns The extracted Zcash transaction instance
+   * @throws Error if the PSBT is not fully finalized or extraction fails
+   */
+  override extractTransaction(): ZcashTransaction {
+    return ZcashTransaction.fromWasm(this.wasm.extract_zcash_transaction());
+  }
 }

packages/wasm-utxo/js/transaction.ts

@@ -1,21 +1,48 @@
 import { WasmDashTransaction, WasmTransaction, WasmZcashTransaction } from "./wasm/wasm_utxo.js";
 
+/**
+ * Common interface for all transaction types
+ */
+export interface ITransaction {
+  toBytes(): Uint8Array;
+  getId(): string;
+}
+
 /**
  * Transaction wrapper (Bitcoin-like networks)
  *
  * Provides a camelCase, strongly-typed API over the snake_case WASM bindings.
  */
-export class Transaction {
+export class Transaction implements ITransaction {
   private constructor(private _wasm: WasmTransaction) {}
 
   static fromBytes(bytes: Uint8Array): Transaction {
     return new Transaction(WasmTransaction.from_bytes(bytes));
   }
 
+  /**
+   * @internal Create from WASM instance directly (avoids re-parsing bytes)
+   */
+  static fromWasm(wasm: WasmTransaction): Transaction {
+    return new Transaction(wasm);
+  }
+
   toBytes(): Uint8Array {
     return this._wasm.to_bytes();
   }
 
+  /**
+   * Get the transaction ID (txid)
+   *
+   * The txid is the double SHA256 of the transaction bytes (excluding witness
+   * data for segwit transactions), displayed in reverse byte order as is standard.
+   *
+   * @returns The transaction ID as a hex string
+   */
+  getId(): string {
+    return this._wasm.get_txid();
+  }
+
   /**
    * Get the virtual size of the transaction
    *
@@ -40,17 +67,36 @@ export class Transaction {
  *
  * Provides a camelCase, strongly-typed API over the snake_case WASM bindings.
  */
-export class ZcashTransaction {
+export class ZcashTransaction implements ITransaction {
   private constructor(private _wasm: WasmZcashTransaction) {}
 
   static fromBytes(bytes: Uint8Array): ZcashTransaction {
     return new ZcashTransaction(WasmZcashTransaction.from_bytes(bytes));
   }
 
+  /**
+   * @internal Create from WASM instance directly (avoids re-parsing bytes)
+   */
+  static fromWasm(wasm: WasmZcashTransaction): ZcashTransaction {
+    return new ZcashTransaction(wasm);
+  }
+
   toBytes(): Uint8Array {
     return this._wasm.to_bytes();
   }
 
+  /**
+   * Get the transaction ID (txid)
+   *
+   * The txid is the double SHA256 of the full Zcash transaction bytes,
+   * displayed in reverse byte order as is standard.
+   *
+   * @returns The transaction ID as a hex string
+   */
+  getId(): string {
+    return this._wasm.get_txid();
+  }
+
   /**
    * @internal
    */
@@ -64,17 +110,36 @@ export class ZcashTransaction {
  *
  * Round-trip only: bytes -> parse -> bytes.
  */
-export class DashTransaction {
+export class DashTransaction implements ITransaction {
   private constructor(private _wasm: WasmDashTransaction) {}
 
   static fromBytes(bytes: Uint8Array): DashTransaction {
     return new DashTransaction(WasmDashTransaction.from_bytes(bytes));
   }
 
+  /**
+   * @internal Create from WASM instance directly (avoids re-parsing bytes)
+   */
+  static fromWasm(wasm: WasmDashTransaction): DashTransaction {
+    return new DashTransaction(wasm);
+  }
+
   toBytes(): Uint8Array {
     return this._wasm.to_bytes();
   }
 
+  /**
+   * Get the transaction ID (txid)
+   *
+   * The txid is the double SHA256 of the full Dash transaction bytes,
+   * displayed in reverse byte order as is standard.
+   *
+   * @returns The transaction ID as a hex string
+   */
+  getId(): string {
+    return this._wasm.get_txid();
+  }
+
   /**
    * @internal
    */

packages/wasm-utxo/src/fixed_script_wallet/bitgo_psbt/mod.rs

@@ -1147,6 +1147,61 @@ impl BitGoPsbt {
         }
     }
 
+    /// Extract the Bitcoin transaction directly (for BitcoinLike networks only)
+    ///
+    /// # Returns
+    /// * `Ok(Transaction)` - The extracted transaction
+    /// * `Err(String)` - If not BitcoinLike or extraction fails
+    pub fn extract_bitcoin_tx(self) -> Result<miniscript::bitcoin::Transaction, String> {
+        match self {
+            BitGoPsbt::BitcoinLike(psbt, _) => psbt
+                .extract_tx()
+                .map_err(|e| format!("Failed to extract transaction: {}", e)),
+            _ => Err("extract_bitcoin_tx only supported for BitcoinLike networks".to_string()),
+        }
+    }
+
+    /// Extract the Dash transaction parts directly
+    ///
+    /// # Returns
+    /// * `Ok(DashTransactionParts)` - The extracted transaction parts
+    /// * `Err(String)` - If not Dash or extraction fails
+    pub fn extract_dash_tx(self) -> Result<crate::dash::transaction::DashTransactionParts, String> {
+        use miniscript::bitcoin::consensus::serialize;
+        match self {
+            BitGoPsbt::Dash(dash_psbt, _) => {
+                let tx = dash_psbt
+                    .psbt
+                    .extract_tx()
+                    .map_err(|e| format!("Failed to extract transaction: {}", e))?;
+                let tx_bytes = serialize(&tx);
+                crate::dash::transaction::decode_dash_transaction_parts(&tx_bytes)
+                    .map_err(|e| format!("Failed to decode Dash transaction: {}", e))
+            }
+            _ => Err("extract_dash_tx only supported for Dash networks".to_string()),
+        }
+    }
+
+    /// Extract the Zcash transaction parts directly
+    ///
+    /// # Returns
+    /// * `Ok(ZcashTransactionParts)` - The extracted transaction parts
+    /// * `Err(String)` - If not Zcash or extraction fails
+    pub fn extract_zcash_tx(
+        self,
+    ) -> Result<crate::zcash::transaction::ZcashTransactionParts, String> {
+        match self {
+            BitGoPsbt::Zcash(zcash_psbt, _) => {
+                let bytes = zcash_psbt
+                    .extract_tx()
+                    .map_err(|e| format!("Failed to extract transaction: {}", e))?;
+                crate::zcash::transaction::decode_zcash_transaction_parts(&bytes)
+                    .map_err(|e| format!("Failed to decode Zcash transaction: {}", e))
+            }
+            _ => Err("extract_zcash_tx only supported for Zcash networks".to_string()),
+        }
+    }
+
     /// Extract a half-signed transaction in legacy format for p2ms-based script types.
     ///
     /// This method extracts a transaction where each input has exactly one signature,

packages/wasm-utxo/src/wasm/dash_transaction.rs

@@ -7,6 +7,13 @@ pub struct WasmDashTransaction {
     parts: crate::dash::transaction::DashTransactionParts,
 }
 
+impl WasmDashTransaction {
+    /// Create from parts (internal use)
+    pub(crate) fn from_parts(parts: crate::dash::transaction::DashTransactionParts) -> Self {
+        WasmDashTransaction { parts }
+    }
+}
+
 #[wasm_bindgen]
 impl WasmDashTransaction {
     /// Deserialize a Dash transaction from bytes (supports EVO special tx extra payload).
@@ -24,4 +31,26 @@ impl WasmDashTransaction {
             WasmUtxoError::new(&format!("Failed to serialize Dash transaction: {}", e))
         })
     }
+
+    /// Get the transaction ID (txid)
+    ///
+    /// The txid is the double SHA256 of the full Dash transaction bytes,
+    /// displayed in reverse byte order (big-endian) as is standard.
+    ///
+    /// # Returns
+    /// The transaction ID as a hex string
+    ///
+    /// # Errors
+    /// Returns an error if the transaction cannot be serialized
+    pub fn get_txid(&self) -> Result<String, WasmUtxoError> {
+        use miniscript::bitcoin::hashes::{sha256d, Hash};
+        use miniscript::bitcoin::Txid;
+        let tx_bytes = crate::dash::transaction::encode_dash_transaction_parts(&self.parts)
+            .map_err(|e| {
+                WasmUtxoError::new(&format!("Failed to serialize Dash transaction: {}", e))
+            })?;
+        let hash = sha256d::Hash::hash(&tx_bytes);
+        let txid = Txid::from_raw_hash(hash);
+        Ok(txid.to_string())
+    }
 }

packages/wasm-utxo/src/wasm/fixed_script_wallet/mod.rs

@@ -585,6 +585,19 @@ impl BitGoPsbt {
         self.psbt.network().to_string()
     }
 
+    /// Get the network type for transaction extraction
+    ///
+    /// Returns "bitcoin", "dash", or "zcash" to indicate which transaction
+    /// wrapper class should be used in TypeScript.
+    pub fn get_network_type(&self) -> String {
+        use crate::fixed_script_wallet::bitgo_psbt::BitGoPsbt as InnerBitGoPsbt;
+        match &self.psbt {
+            InnerBitGoPsbt::BitcoinLike(_, _) => "bitcoin".to_string(),
+            InnerBitGoPsbt::Dash(_, _) => "dash".to_string(),
+            InnerBitGoPsbt::Zcash(_, _) => "zcash".to_string(),
+        }
+    }
+
     /// Get the transaction version
     pub fn version(&self) -> i32 {
         self.psbt.psbt().unsigned_tx.version.0
@@ -1490,6 +1503,53 @@ impl BitGoPsbt {
             .map_err(|e| WasmUtxoError::new(&e))
     }
 
+    /// Extract the final transaction as a WasmTransaction (for BitcoinLike networks)
+    ///
+    /// This avoids re-parsing bytes by returning the transaction directly.
+    /// Only valid for Bitcoin-like networks (not Dash or Zcash).
+    pub fn extract_bitcoin_transaction(
+        &self,
+    ) -> Result<crate::wasm::transaction::WasmTransaction, WasmUtxoError> {
+        let tx = self
+            .psbt
+            .clone()
+            .extract_bitcoin_tx()
+            .map_err(|e| WasmUtxoError::new(&e))?;
+        Ok(crate::wasm::transaction::WasmTransaction::from_tx(tx))
+    }
+
+    /// Extract the final transaction as a WasmDashTransaction (for Dash networks)
+    ///
+    /// This avoids re-parsing bytes by returning the transaction directly.
+    /// Only valid for Dash networks.
+    pub fn extract_dash_transaction(
+        &self,
+    ) -> Result<crate::wasm::dash_transaction::WasmDashTransaction, WasmUtxoError> {
+        let parts = self
+            .psbt
+            .clone()
+            .extract_dash_tx()
+            .map_err(|e| WasmUtxoError::new(&e))?;
+        Ok(crate::wasm::dash_transaction::WasmDashTransaction::from_parts(parts))
+    }
+
+    /// Extract the final transaction as a WasmZcashTransaction (for Zcash networks)
+    ///
+    /// This avoids re-parsing bytes by returning the transaction directly.
+    /// Only valid for Zcash networks.
+    pub fn extract_zcash_transaction(
+        &self,
+    ) -> Result<crate::wasm::transaction::WasmZcashTransaction, WasmUtxoError> {
+        let parts = self
+            .psbt
+            .clone()
+            .extract_zcash_tx()
+            .map_err(|e| WasmUtxoError::new(&e))?;
+        Ok(crate::wasm::transaction::WasmZcashTransaction::from_parts(
+            parts,
+        ))
+    }
+
     /// Extract a half-signed transaction in legacy format for p2ms-based script types.
     ///
     /// This method extracts a transaction where each input has exactly one signature,