script.js

'use strict'
// 6:40 AM start
// 6:59 AM parsing complete
// 7:12 AM part 1
// 7:34 AM part 2


// Setup
const validYear = (year, min, max) => {
    year = parseInt(year)
    return min <= year && year <= max
}

const validHeight = height => {
    const parsed = /^(\d+)(cm|in)$/.exec(height)
  
    if (parsed) {
        let [height, unit] = parsed?.slice(1)
        height = parseInt(height)
        if (unit == 'in') {
            return 59 <= height && height <= 76
        } else {
            return 150 <= height && height <= 193
        }
    }
    return false
}

const validPattern = (val, pattern) => {
    return pattern.test(val)
}

const optional = () => true

const KEYS = {
    byr: true,
    iyr: true,
    eyr: true,
    hgt: true,
    hcl: true,
    ecl: true,
    pid: true,
    cid: false
}

const VALIDATORS = {
    byr: {
        validator: validYear,
        args: [1920, 2002]
    },
    iyr: {
        validator: validYear,
        args: [2010, 2020]
    },
    eyr: {
        validator: validYear,
        args: [2020, 2030]
    },
    hgt:{
        validator: validHeight,
        args: []
    },
    hcl: {
        validator: validPattern,
        args: [/^#[0-9a-f]{6}$/]
    },
    ecl: {
        validator: validPattern,
        args: [/^amb|blu|brn|gry|grn|hzl|oth$/]
    },
    pid: {
        validator: validPattern,
        args: [/^\d{9}$/]
    },
    cid: {
        validator: optional,
        args: []
    }
}

const processCredential = credential => {
    return credential.split(/ |\n/)
        .reduce((prev, curr) => {
            const [key, val] = curr.split(':')
            prev[key] = val
            return prev
        }, {})
}

const isCredentialValid = credential => {
    for (const key in KEYS) {
        if(KEYS[key] && !credential[key]){
            return false
        }
    }
    return true
}

const isCredentialFullyValid = credential => {
    for (const key in VALIDATORS) {
        const {validator, args} = VALIDATORS[key]
        if(!validator(credential[key], ...args)) {
            return false
        }
    }
    return true
}

// Part 1
// ======

const part1 = input => {
    return input.split('\n\n')
        .map(processCredential)
        .filter(isCredentialValid).length
}

// Part 2
// ======

const part2 = input => {
    return input.split('\n\n')
        .map(processCredential)
        .filter(isCredentialFullyValid).length
}

module.exports = { part1, part2 }