advent-of-code/2020/day6/day6.js

#!/bin/node

const fs = require('fs');

fs.readFile('input.txt', (err, data) => {
    const groups = data.toString()
        .split('\n\n')
        .map(group => group.split('\n')
            .filter(person => person.length > 0));

    let q1 = 0;
    let q2 = 0;
    for (const group of groups) {
        let q1Questions = [];
        let q2Questions = [];

        for (const person of group) {
            for (const question of person) {
                if (q1Questions.indexOf(question) < 0) {
                    q1Questions.push(question);
                }

                if (q2Questions.indexOf(question) < 0 && group.every(person => person.indexOf(question) >= 0)) {
                    q2Questions.push(question);
                }
            }
        }

        q1 += q1Questions.length;
        q2 += q2Questions.length;
    }

    console.log(q1, q2);
});