node code cleanup

script.js

const fs = require("fs")
const fsPromises = require("fs/promises")

;(async () => {
  try {
    // passing utf-8 here (the encoding argument) makes it return a string
    const fileList = await fsPromises.readFile("./exclude", "utf-8")

    const excludeList = fileList.split("\n")

    const allFileList = await fsPromises.readdir("./")

    const finalFileList = allFileList.filter((file) => {
      if (excludeList.includes(file)) return false
      if (file.indexOf(".") == 0) return false
      if (file.split(".").length == 1) return false
      return true
    })

    // this works because async functions return a promise,
    // so we map `finalFileList` to a list of promises,
    // then await them all in parallel via Promise.all
    await Promise.all(
      finalFileList.map(async (file) => {
        const extension = file.split(".")[1]

        // if you pass `{ recursive: true }` to mkdir,
        // it'll create the directory if it exists, but do nothing otherwise
        await fsPromises.mkdir(`./${extension}`, { recursive: true })

        await fsPromises.rename(file, `./${extension}/${file}`)

        console.log(`File ${file} moved successfully`)
      })
    )
  } catch (error) {
    // the error stack is generally more useful than just the message
    // but we also fall back to the message in case there is no stack
    console.log(error.stack || error.message || error)
  }
})()