AoC 2022 day 9

const fs = require('fs');
const eol = require('os').EOL;

const startTime = new Date().getTime();
let part1 = part2 = 0;
let moves = fs.readFileSync(__dirname + "/data.txt", 'utf8').split(eol).map(a => a.split(" "));

const dirs = {
    R: [1, 0],
    L: [-1, 0],
    U: [0, -1],
    D: [0, 1],
};

function solve(ropeLength) {
    let tSet = new Set();
    let rope = new Array(ropeLength).fill().map(u => [0, 0]);
    moves.forEach(move => {
        let [direction, steps] = move;
        for (let i = 0; i < steps; i++) {
            rope[0] = [rope[0][0] + dirs[direction][0], rope[0][1] + dirs[direction][1]];
            for (let j = 1; j < ropeLength; j++) {
                let dx = rope[j - 1][0] - rope[j][0];
                let dy = rope[j - 1][1] - rope[j][1];
                if (Math.abs(dx) > 1 || Math.abs(dy) > 1) {
                    rope[j][0] += Math.sign(dx);
                    rope[j][1] += Math.sign(dy);
                }
            }
            tSet.add(rope[ropeLength - 1].join("-"));
        }
    });
    return tSet.size;
}
part1 = solve(2);
part2 = solve(10);
let time = new Date().getTime() - startTime;
console.log(`Part 1: ${part1}\nPart 2: ${part2}\nTimer: ${time} ms`);