Advent of Code 2020 Day 3 TypeScript

day3.ts

import { readFileSync } from 'fs';

const map = readFileSync('input.txt').toString('utf8').split('\n');
const patternWidth = map[0].length;

const countTreesInSlope = (right: number, down: number) => {
    let totalTrees = 0;
    let y= 0;
    for (let x = 0; x < map.length; x = x + down) {
        const line = map[x];
        if (line.charAt(y) === '#') {
            totalTrees = totalTrees + 1;
        }
        if (y + right < patternWidth) {
            y = y + right;
        } else {
            y = y + right - patternWidth;
        }
    }

    return totalTrees;
}

console.log(`Chapter one: ${countTreesInSlope(3, 1)}`);

let slopes = [
    countTreesInSlope(1, 1),
    countTreesInSlope(3, 1),
    countTreesInSlope(5, 1),
    countTreesInSlope(7, 1),
    countTreesInSlope(1, 2)
];

console.log(`Chapter two: ${slopes.reduce((a, b) => a * b)}`);