Add toPsbt() method to Transaction class

package-lock.json

@@ -329,6 +329,11 @@
         "safe-buffer": "^5.1.2"
       }
     },
+    "buffer-reverse": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/buffer-reverse/-/buffer-reverse-1.0.1.tgz",
+      "integrity": "sha1-SSg8jvpvkBvAH6MwTQYCeXGuL2A="
+    },
     "builtin-modules": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/builtin-modules/-/builtin-modules-1.1.1.tgz",

package.json

@@ -52,6 +52,7 @@
     "bip66": "^1.1.0",
     "bitcoin-ops": "^1.4.0",
     "bs58check": "^2.0.0",
+    "buffer-reverse": "^1.0.1",
     "create-hash": "^1.1.0",
     "create-hmac": "^1.1.3",
     "merkle-lib": "^2.0.10",

src/transaction.js

@@ -1,11 +1,13 @@
 'use strict';
 Object.defineProperty(exports, '__esModule', { value: true });
+const bip174_1 = require('bip174');
 const bufferutils = require('./bufferutils');
 const bufferutils_1 = require('./bufferutils');
 const bcrypto = require('./crypto');
 const bscript = require('./script');
 const script_1 = require('./script');
 const types = require('./types');
+const reverse = require('buffer-reverse');
 const typeforce = require('typeforce');
 const varuint = require('varuint-bitcoin');
 function varSliceSize(someScript) {
@@ -378,6 +380,28 @@ class Transaction {
   toHex() {
     return this.toBuffer(undefined, undefined).toString('hex');
   }
+  toPsbt() {
+    const outputs = this.outs.map(output => ({
+      script: output.script.toString('hex'),
+      tokens: output.value,
+    }));
+    const utxos = this.ins.map(input => ({
+      id: reverse(input.hash).toString('hex'),
+      vout: input.index,
+      sequence: input.sequence,
+    }));
+    const timelock = this.locktime;
+    const { version } = this;
+    const { psbt } = bip174_1.createPsbt({
+      outputs,
+      utxos,
+      timelock,
+      version,
+    });
+    // TODO: Add signature data to PSBT
+    // TODO: Merge with imported PSBT if exists so we don't lose data
+    return psbt;
+  }
   setInputScript(index, scriptSig) {
     typeforce(types.tuple(types.Number, types.Buffer), arguments);
     this.ins[index].script = scriptSig;

ts_src/transaction.ts

@@ -1,3 +1,4 @@
+import { createPsbt } from 'bip174';
 import * as bufferutils from './bufferutils';
 import { reverseBuffer } from './bufferutils';
 import * as bcrypto from './crypto';
@@ -5,6 +6,7 @@ import * as bscript from './script';
 import { OPS as opcodes } from './script';
 import * as types from './types';
 
+const reverse = require('buffer-reverse');
 const typeforce = require('typeforce');
 const varuint = require('varuint-bitcoin');
 
@@ -501,6 +503,35 @@ export class Transaction {
     return this.toBuffer(undefined, undefined).toString('hex');
   }
 
+  toPsbt(): string {
+    const outputs = this.outs.map(output => ({
+      script: output.script.toString('hex'),
+      tokens: (output as Output).value,
+    }));
+
+    const utxos = this.ins.map(input => ({
+      id: reverse(input.hash).toString('hex'),
+      vout: input.index,
+      sequence: input.sequence,
+    }));
+
+    const timelock = this.locktime;
+    const { version } = this;
+
+    const { psbt } = createPsbt({
+      outputs,
+      utxos,
+      timelock,
+      version,
+    });
+
+    // TODO: Add signature data to PSBT
+
+    // TODO: Merge with imported PSBT if exists so we don't lose data
+
+    return psbt;
+  }
+
   setInputScript(index: number, scriptSig: Buffer): void {
     typeforce(types.tuple(types.Number, types.Buffer), arguments);
 

types/transaction.d.ts

@@ -52,6 +52,7 @@ export declare class Transaction {
     getId(): string;
     toBuffer(buffer?: Buffer, initialOffset?: number): Buffer;
     toHex(): string;
+    toPsbt(): string;
     setInputScript(index: number, scriptSig: Buffer): void;
     setWitness(index: number, witness: Buffer[]): void;
     private __byteLength;