Bitcoin Output Descriptor

This Node.js library is used to handle Bitcoin output descriptors.

Particularly, it will parse any standard Bitcoin output descriptor (as defined here) and generate output (or pubkey) scripts and addresses that conform to that descriptor.

Installation

npm install @blockchainofthings/btc-output-descriptor

Usage

Parsing an output descriptor

const BtcOutDesc = require('@blockchainofthings/btc-output-descriptor');

const expression = BtcOutDesc.parse(
    "wpkh([d34db33f/44'/0'/0']xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL/1/*)",
    'main'
);

The second argument ('main' in the sample code above) is used to specify the Bitcoin network. Valid values: main (or bitcoin), testnet, signet, and regtest.

Note: if no Bitcoin network is specified, 'main' is used.

Setting a key range

When an output descriptor includes an extended (BIP32) public or private key with a derivation path that ends with /* or *' (as in the sample code above), a key range should be specified to restrict the set of output scripts and addresses that will be generated.

if (expression.hasRangeKey) {
    expression.keyRange = {
        startIdx: 0,
        count: 10
    };
}

Note: if not explicitly set, the key range will include 1,000 key sets starting at index 0.

Generating output scripts

console.log(expression.outputScripts);

Sample output:

[
  <Buffer 00 14 2a 05 c2 14 61 7c 9b 04 34 c9 2d 05 83 20 0a 85 ef 61 81 8f>,
  <Buffer 00 14 49 b2 f8 1e ea 1e cb 5b c9 7d 78 f2 d8 f8 9d 9c 86 1c 3c f2>,
  <Buffer 00 14 b6 37 5a 30 c7 83 3b 2f 28 e0 d5 5c 18 0d 12 b4 3d 4d fa a4>,
  <Buffer 00 14 12 c7 cd f9 3e 29 95 32 e2 39 c4 21 42 20 dd da cd 67 db 55>,
  <Buffer 00 14 17 c8 f3 69 b2 6c d7 70 ce b6 97 1e f5 ef a8 ff d7 c6 e1 47>,
  <Buffer 00 14 0c 80 19 20 b8 23 2b 35 01 76 28 dc e9 22 8c 8e 67 a4 75 41>,
  <Buffer 00 14 c1 d4 72 d4 eb 68 ea ac 57 0c 6a 93 54 1f 8b 78 75 b0 2e 8a>,
  <Buffer 00 14 e0 2d 77 0c a0 88 ba 08 4b 34 45 c5 b9 48 41 13 21 36 22 23>,
  <Buffer 00 14 3a 9a 28 8e f2 bd 4b 6d c5 2f 75 39 83 a4 7a ba 24 bf 57 37>,
  <Buffer 00 14 68 26 b6 a0 37 40 59 5d 21 50 92 94 5e 0b 50 5f 58 64 a3 74>
]

Generating addresses

console.log(expression.addresses);

Sample output:

[
  'bc1q9gzuy9rp0jdsgdxf95zcxgq2shhkrqv0wy2wek',
  'bc1qfxe0s8h2rm94hjta0red37yanjrpc08jxsjzhg',
  'bc1qkcm45vx8svaj728q64wpsrgjks75m74ytsz54h',
  'bc1qztrum7f79x2n9c3ecss5ygxamtxk0k643jyxh7',
  'bc1qzly0x6djdnthpn4kju00tmaglltudc284tpqgx',
  'bc1qpjqpjg9cyv4n2qtk9rwwjg5v3en6ga2pggr3sj',
  'bc1qc828948tdr42c4cvd2f4g8ut0p6mqt52gjal73',
  'bc1quqkhwr9q3zaqsje5ghzmjjzpzvsnvg3r8du84d',
  'bc1q82dz3rhjh49km3f0w5uc8fr6hgjt74ehgrzrcy',
  'bc1qdqntdgphgpv46g2sj229uz6stavxfgm5ck33lg'
]

Note: in cases where no address is defined for that type of output—including pk(...), multi(...), sortedmulti(...), and some raw(...) descriptors—an empty array is returned.

License

This Node.js module is released under the MIT License. Feel free to fork, and modify!

Copyright © 2021-2022, Blockchain of Things Inc.