Bitcoin Wallet Import Format encoding/decoding module.
var wif = require('wif')
var privateKey = Buffer.from('0000000000000000000000000000000000000000000000000000000000000001', 'hex')
var key = wif.encode(128, privateKey, true) // for the testnet use: wif.encode(239, ...
// => KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn
var obj = wif.decode(key)
// => {
// version: 128,
// privateKey: <Buffer 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01>,
// compressed: true
//}
wif.decode(key, 0x09)
// => Error: Invalid network version
// alternative syntax
wif.encode(obj)
// => KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn