Take a directory of files and move them into directories based on the first letter of the file

sort-files-into-alphabetical-directories.js

// Usage: 
// 1. npm init -y && npm i minimist
// 2. node sort-files-into-alphabetical-directories.js /directory-of-files /directory-of-files/output

const fs = require("fs");
const path = require("path");
const argv = require("minimist")(process.argv.slice(2));

const alphabet = [..."abcdefghijklmnopqrstuvwxyz"];

const readPath = argv._[0];
const outputPath = argv._[1];

fs.readdir(readPath, (err, files) => {
  alphabet.forEach((letter) => {
    const letterOutputPath = path.join(outputPath, letter.toLocaleUpperCase());

    if (!fs.existsSync(letterOutputPath)) {
      fs.mkdirSync(letterOutputPath);
    }

    const toMatch = new RegExp(`^(${letter})(?:.*)$`, "g");
    files
      .filter((fileName) => fileName.toLocaleLowerCase().match(toMatch))
      .forEach((fileName) => {
        const oldPath = path.join(readPath, fileName);
        const newPath = path.join(
          outputPath,
          letter.toLocaleUpperCase(),
          fileName
        );
        fs.rename(oldPath, newPath, (err) => {
          if (err) {
            throw err;
          }

          console.log("Moved", `"${fileName}"`, "to", newPath);
        });
      });
  });
});