util/btc.js

import varuint from 'varuint-bitcoin'
import wif from 'wif'

/**
 * Check if a WIF is valid for a specific CoinNetwork
 * @param  {string} key - Base58 WIF Private Key
 * @param  {CoinNetwork} network
 * @return {Boolean}
 */
function isValidWIF (key, network) {
  try {
    let dec = wif.decode(key)

    if (network) {
      return dec.version === network.wif
    } else {
      return true
    }
  } catch (e) {
    console.error(e)
    return false
  }
}

module.exports = {
  isValidWIF,
  varIntBuffer: varuint.encode
}