AdventOfCode2020/day_4/task_2.js

const fs = require('fs');
const file = fs.readFileSync(__dirname + '/input.txt').toString('utf-8');
const passports = file.split('\n\n');

const fieldNames = {
    byr: 'Birth year',
    iyr: 'Issue year',
    eyr: 'Expiration year',
    hgt: 'Height',
    hcl: 'Hair color',
    ecl: 'Eye color',
    pid: 'Passport ID',
    cid: 'Country ID'
}, passportFields = Object.keys(fieldNames);

const bypassed = [ 'cid' ]; // These are ignored

const validationFuncs = {
    byr: value => value >= 1920 && value <= 2002,
    iyr: value => value >= 2010 && value <= 2020,
    eyr: value => value >= 2020 && value <= 2030,
    hgt: value => {
        let end = value.split(/[0-9]+/)[1];
        let num = value.split(end)[0];
        if (!end || !num) return false;
        if (end == 'cm') {
            return (num >= 150 && num <= 193);
        } else if (end == 'in')
            return (num >= 59 && num <= 76);
        else return false;
    },
    hcl: value => value?.match(/#[0-9|a-f]{6}/) ? true : false,
    ecl: value => value?.match(/amb|blu|brn|gry|grn|hzl|oth/) ? true : false,
    pid: value => value?.match(/^[0-9]{9}$/) ? true : false,
    cid: value => true
}

let invalid = 0;
let invalidStats = {}
passportFields.forEach(field => invalidStats[field] = 0);

passports.forEach(passport => {
    passport = passport
        .replace(/\n/g, ' ')
        .split(' ');
    
    let inv = false;
    passportFields.forEach(field => {
        let h = passport.filter(h => h.split(':')[0] == field);
        if (h?.[0]) h = h[0].split(':');
        
        if (bypassed.indexOf(field) > -1) return;
        if (!(h[1] && validationFuncs[field](h[1]))) {
            inv = true;
            invalidStats[field] += 1;
        }
    });
    if (inv) invalid++;
});

let statsStr = ``; 
for (const [key, value] of Object.entries(invalidStats))
    statsStr += `${fieldNames[key]}: ${value}\n`;

console.log(statsStr);
console.log(`Invalid passports: ${invalid}`);
console.log(`Valid passports: ${passports.length - invalid}`);
console.log(`Total passports: ${passports.length}`);