Advent of Code 2023 #01

aoc01.js

const { readFile } = require('node:fs/promises');

const filename = 'input.txt';
const firstDigitRegex = /\d/;
const lastDigitRegex = /\d[a-z]*$/;

const parseCalibrationFile = async (file) => {
  const data = (await readFile('input.txt', 'utf8')).split('\n');
  const sum = data.reduce((acc, line) => {
    const firstDigit = parseInt(line.match(firstDigitRegex) ?? '0');
    const lastDigit = parseInt(line.match(lastDigitRegex) ?? '0');
    return acc + firstDigit * 10 + lastDigit;
  }, 0);
  return sum;
};

parseCalibrationFile(filename).then(console.log);