Reactive recursive read directory nodejs

direcorySize.ts

export function directorySize(path: string): Promise<number> {
  return readdirRecursive(path)
  .reduce((result: any, a: any) => {
    result += a.stat.size
    return result
  }, 0)
}

directorySize('./node_modules')
.then((size) => {
  console.log('Total size %d MB', size * 1e-6)
})
  
/**
 * 
 * ❯ time node lib/fs/fs.js
 * Total size 3.848 MB
 * node lib/fs/fs.js  0.20s user 0.05s system 124% cpu 0.204 total
 **/

fs.ts

import * as fs from 'fs'
import {create} from '@most/create'
import {Stream, of} from 'most'

export function readdir(path: string, options?: any): Stream<any> {
  return create((add, end, error) => {
    (fs.readdir as any)(path, options, function(err: NodeJS.ErrnoException, files: string[]) {
      if (err) {
        return error(err)
      }

      files.map(e => add(`${path}/${e}`))
      end()
    })
  })
}

export function stat(path: string): Stream<any> {
  return create((add, end, error) => {
    fs.stat(path, function(err: NodeJS.ErrnoException, stats: fs.Stats) {
      if (err) {
        return error(err)
      }

      add(stats)
      end()
    })
  })
}

export function readdirRecursive(path: string): Stream<any> {
  return readdir(path)
  .flatMap((filePath: string) => {
    return of(filePath)
    .flatMap((e: string) => stat(e))
    .map((stat: fs.Stats) => {
      return {path: filePath, stat: stat}
    })
  })
  .flatMap((e) => {
    return e.stat.isDirectory() ? readdirRecursive(e.path) : of(e)
  })
}

readdirRecursive('./node_modules')
.observe((e) => {
  console.log(e)
})