Improve code re-use for redeem script checks

src/psbt.js

@@ -3,6 +3,17 @@ Object.defineProperty(exports, '__esModule', { value: true });
 const bip174_1 = require('bip174');
 const payments = require('./payments');
 const transaction_1 = require('./transaction');
+const checkRedeemScript = (inputIndex, scriptPubKey, redeemScript) => {
+  const redeemScriptOutput = payments.p2sh({
+    redeem: { output: redeemScript },
+  }).output;
+  // If a redeemScript is provided, the scriptPubKey must be for that redeemScript
+  if (Buffer.compare(scriptPubKey, redeemScriptOutput) !== 0) {
+    throw new Error(
+      `Redeem script for input #${inputIndex} doesn't match the scriptPubKey in the prevout`,
+    );
+  }
+};
 class Psbt extends bip174_1.Psbt {
   constructor() {
     super();
@@ -51,31 +62,17 @@ class Psbt extends bip174_1.Psbt {
       if (input.redeemScript) {
         const prevoutIndex = unsignedTx.ins[inputIndex].index;
         const prevout = nonWitnessUtxoTx.outs[prevoutIndex];
-        const redeemScriptOutput = payments.p2sh({
+        checkRedeemScript(inputIndex, prevout.script, input.redeemScript);
-          redeem: { output: input.redeemScript },
-        }).output;
-        // If a redeemScript is provided, the scriptPubKey must be for that redeemScript
-        if (Buffer.compare(prevout.script, redeemScriptOutput) !== 0) {
-          throw new Error(
-            `Redeem script for input #${inputIndex} doesn't match the scriptPubKey in the prevout`,
-          );
-        }
       }
     } else if (input.witnessUtxo) {
       if (input.redeemScript) {
-        const redeemScriptOutput = payments.p2sh({
+        checkRedeemScript(
-          redeem: { output: input.redeemScript },
+          inputIndex,
-        }).output;
+          input.witnessUtxo.script,
-        // If a redeemScript is provided, the scriptPubKey must be for that redeemScript
+          input.redeemScript,
-        if (
-          Buffer.compare(input.witnessUtxo.script, redeemScriptOutput) !== 0
-        ) {
-          throw new Error(
-            `Redeem script for input #${inputIndex} doesn't match the scriptPubKey in the prevout`,
         );
       }
     }
-    }
     // TODO: Get hash to sign
     const hash = Buffer.alloc(32);
     const partialSig = {

ts_src/psbt.ts

@@ -3,6 +3,23 @@ import { Signer } from './ecpair';
 import * as payments from './payments';
 import { Transaction } from './transaction';
 
+const checkRedeemScript = (
+  inputIndex: number,
+  scriptPubKey: Buffer,
+  redeemScript: Buffer,
+): void => {
+  const redeemScriptOutput = payments.p2sh({
+    redeem: { output: redeemScript },
+  }).output as Buffer;
+
+  // If a redeemScript is provided, the scriptPubKey must be for that redeemScript
+  if (Buffer.compare(scriptPubKey, redeemScriptOutput) !== 0) {
+    throw new Error(
+      `Redeem script for input #${inputIndex} doesn't match the scriptPubKey in the prevout`,
+    );
+  }
+};
+
 export class Psbt extends PsbtBase {
   constructor() {
     super();
@@ -53,34 +70,17 @@ export class Psbt extends PsbtBase {
       if (input.redeemScript) {
         const prevoutIndex = unsignedTx.ins[inputIndex].index;
         const prevout = nonWitnessUtxoTx.outs[prevoutIndex];
-
+        checkRedeemScript(inputIndex, prevout.script, input.redeemScript);
-        const redeemScriptOutput = payments.p2sh({
-          redeem: { output: input.redeemScript },
-        }).output as Buffer;
-
-        // If a redeemScript is provided, the scriptPubKey must be for that redeemScript
-        if (Buffer.compare(prevout.script, redeemScriptOutput) !== 0) {
-          throw new Error(
-            `Redeem script for input #${inputIndex} doesn't match the scriptPubKey in the prevout`,
-          );
-        }
       }
     } else if (input.witnessUtxo) {
       if (input.redeemScript) {
-        const redeemScriptOutput = payments.p2sh({
+        checkRedeemScript(
-          redeem: { output: input.redeemScript },
+          inputIndex,
-        }).output as Buffer;
+          input.witnessUtxo.script,
-
+          input.redeemScript,
-        // If a redeemScript is provided, the scriptPubKey must be for that redeemScript
-        if (
-          Buffer.compare(input.witnessUtxo.script, redeemScriptOutput) !== 0
-        ) {
-          throw new Error(
-            `Redeem script for input #${inputIndex} doesn't match the scriptPubKey in the prevout`,
         );
       }
     }
-    }
 
     // TODO: Get hash to sign
     const hash = Buffer.alloc(32);