Get wif from mnemonic for certain path.

getWif.js

const {hd, KeyRing} = require('bcoin');
const {HDPrivateKey} = hd;

const mnemonic = 'midnight volcano start infant error drama bulk disorder'
  + ' mouse key cliff climb buyer wage ceiling load express earth trick'
  + ' broccoli siege math hope attend';

const privateKey = HDPrivateKey.fromPhrase(mnemonic);
const deriveSomething = privateKey.derivePath(`m/44'/1/0/0/0`);
const ring = KeyRing.fromPrivate(deriveSomething.privateKey);

console.log(ring.toSecret('regtest'));