day05.js

const md5 = require('md5')

let door_id = 'ugkcyxxp'

let password = '--------'.split``
let index = 0
let found = 0

while (found < 8) {
    let hash = md5(`${door_id}${index}`)
    if (hash.startsWith('00000')) {
        let pos = +hash[5]
        if (pos >= 0 && pos < 8 && password[pos] === '-') {
            password[pos] = hash[6]
            found++
        }
    }
    index++
}

console.log(password.join``)