'use strict'
    let fs = require('fs')
    let path = require('path')

    let pathname = path.resolve('./') + '/test'
    fs.readdir(pathname, (err, files) => {
        files.forEach((filename, index) => {
            let oldpath = pathname + '/' + filename
            let newpath = pathname + '/' + index + '.txt'
            fs.rename(oldpath, newpath, (err) => {
                if (!err) {
                    console.log('success')
                }
            })
        })
    })