Finalize should chain this as well.

src/psbt.js

@@ -187,14 +187,9 @@ class Psbt extends bip174_1.Psbt {
     return c.__FEE_RATE;
   }
   finalizeAllInputs() {
-    const inputResults = range(this.inputs.length).map(idx =>
-      this.finalizeInput(idx),
-    );
-    const result = inputResults.every(val => val === true);
-    return {
-      result,
-      inputResults,
-    };
+    utils_1.checkForInput(this.inputs, 0); // making sure we have at least one
+    range(this.inputs.length).forEach(idx => this.finalizeInput(idx));
+    return this;
   }
   finalizeInput(inputIndex) {
     const input = utils_1.checkForInput(this.inputs, inputIndex);
@@ -203,9 +198,10 @@ class Psbt extends bip174_1.Psbt {
       input,
       this.__CACHE,
     );
-    if (!script) return false;
+    if (!script) throw new Error(`No script found for input #${inputIndex}`);
     const scriptType = classifyScript(script);
-    if (!canFinalize(input, script, scriptType)) return false;
+    if (!canFinalize(input, script, scriptType))
+      throw new Error(`Can not finalize input #${inputIndex}`);
     const { finalScriptSig, finalScriptWitness } = getFinalScripts(
       script,
       scriptType,
@@ -218,9 +214,17 @@ class Psbt extends bip174_1.Psbt {
       this.addFinalScriptSigToInput(inputIndex, finalScriptSig);
     if (finalScriptWitness)
       this.addFinalScriptWitnessToInput(inputIndex, finalScriptWitness);
-    if (!finalScriptSig && !finalScriptWitness) return false;
+    if (!finalScriptSig && !finalScriptWitness)
+      throw new Error(`Unknown error finalizing input #${inputIndex}`);
     this.clearFinalizedInput(inputIndex);
-    return true;
+    return this;
+  }
+  validateAllSignatures() {
+    utils_1.checkForInput(this.inputs, 0); // making sure we have at least one
+    const results = range(this.inputs.length).map(idx =>
+      this.validateSignatures(idx),
+    );
+    return results.reduce((final, res) => res === true && final, true);
   }
   validateSignatures(inputIndex, pubkey) {
     const input = this.inputs[inputIndex];
@@ -261,7 +265,7 @@ class Psbt extends bip174_1.Psbt {
     // as input information is added, then eventually
     // optimize this method.
     const results = [];
-    for (const [i] of this.inputs.entries()) {
+    for (const i of range(this.inputs.length)) {
       try {
         this.signInput(i, keyPair);
         results.push(true);

test/integration/transactions-psbt.js

@@ -225,26 +225,25 @@ describe('bitcoinjs-lib (transactions with psbt)', () => {
       } = inputData
       assert.deepStrictEqual({ hash, index, witnessUtxo, redeemScript }, inputData)
     }
+    const keyPair = p2sh.keys[0]
+    const outputData = {
+      script: p2sh.payment.output, // sending to myself for fun
+      value: 2e4
+    }
 
-    const psbt = new bitcoin.Psbt({ network: regtest })
+    const tx = new bitcoin.Psbt()
       .addInput(inputData)
-      .addOutput({
-        address: regtestUtils.RANDOM_ADDRESS,
-        value: 2e4
-      })
-      .signInput(0, p2sh.keys[0])
-
-    assert.strictEqual(psbt.validateSignatures(0), true)
-    psbt.finalizeAllInputs()
-
-    const tx = psbt.extractTransaction()
+      .addOutput(outputData)
+      .sign(keyPair)
+      .finalizeAllInputs()
+      .extractTransaction()
 
     // build and broadcast to the Bitcoin RegTest network
     await regtestUtils.broadcast(tx.toHex())
 
     await regtestUtils.verify({
       txId: tx.getId(),
-      address: regtestUtils.RANDOM_ADDRESS,
+      address: p2sh.payment.address,
       vout: 0,
       value: 2e4
     })

ts_src/psbt.ts

@@ -233,31 +233,24 @@ export class Psbt extends PsbtBase {
     return c.__FEE_RATE!;
   }
 
-  finalizeAllInputs(): {
-    result: boolean;
-    inputResults: boolean[];
-  } {
-    const inputResults = range(this.inputs.length).map(idx =>
-      this.finalizeInput(idx),
-    );
-    const result = inputResults.every(val => val === true);
-    return {
-      result,
-      inputResults,
-    };
+  finalizeAllInputs(): this {
+    checkForInput(this.inputs, 0); // making sure we have at least one
+    range(this.inputs.length).forEach(idx => this.finalizeInput(idx));
+    return this;
   }
 
-  finalizeInput(inputIndex: number): boolean {
+  finalizeInput(inputIndex: number): this {
     const input = checkForInput(this.inputs, inputIndex);
     const { script, isP2SH, isP2WSH, isSegwit } = getScriptFromInput(
       inputIndex,
       input,
       this.__CACHE,
     );
-    if (!script) return false;
+    if (!script) throw new Error(`No script found for input #${inputIndex}`);
 
     const scriptType = classifyScript(script);
-    if (!canFinalize(input, script, scriptType)) return false;
+    if (!canFinalize(input, script, scriptType))
+      throw new Error(`Can not finalize input #${inputIndex}`);
 
     const { finalScriptSig, finalScriptWitness } = getFinalScripts(
       script,
@@ -272,10 +265,19 @@ export class Psbt extends PsbtBase {
       this.addFinalScriptSigToInput(inputIndex, finalScriptSig);
     if (finalScriptWitness)
       this.addFinalScriptWitnessToInput(inputIndex, finalScriptWitness);
-    if (!finalScriptSig && !finalScriptWitness) return false;
+    if (!finalScriptSig && !finalScriptWitness)
+      throw new Error(`Unknown error finalizing input #${inputIndex}`);
 
     this.clearFinalizedInput(inputIndex);
-    return true;
+    return this;
+  }
+
+  validateAllSignatures(): boolean {
+    checkForInput(this.inputs, 0); // making sure we have at least one
+    const results = range(this.inputs.length).map(idx =>
+      this.validateSignatures(idx),
+    );
+    return results.reduce((final, res) => res === true && final, true);
   }
 
   validateSignatures(inputIndex: number, pubkey?: Buffer): boolean {
@@ -319,7 +321,7 @@ export class Psbt extends PsbtBase {
     // as input information is added, then eventually
     // optimize this method.
     const results: boolean[] = [];
-    for (const [i] of this.inputs.entries()) {
+    for (const i of range(this.inputs.length)) {
       try {
         this.signInput(i, keyPair);
         results.push(true);

types/psbt.d.ts

@@ -20,11 +20,9 @@ export declare class Psbt extends PsbtBase {
     addNonWitnessUtxoToInput(inputIndex: number, nonWitnessUtxo: NonWitnessUtxo): this;
     extractTransaction(disableFeeCheck?: boolean): Transaction;
     getFeeRate(): number;
-    finalizeAllInputs(): {
-        result: boolean;
-        inputResults: boolean[];
-    };
-    finalizeInput(inputIndex: number): boolean;
+    finalizeAllInputs(): this;
+    finalizeInput(inputIndex: number): this;
+    validateAllSignatures(): boolean;
     validateSignatures(inputIndex: number, pubkey?: Buffer): boolean;
     sign(keyPair: Signer): this;
     signAsync(keyPair: SignerAsync): Promise<void>;