fs-safe-copy/lib/Copier/FolderCopier.js

Copy some files easily. Check your copy checksum.

'use strict'
const path = require('path')
const fs = require('fs')
const { FileStat } = require('./FileStat')
const { FileCopier } = require('./FileCopier')
const { TaskQueue } = require('./TaskQueue')
const { promisify } = require('util')
const readDir = promisify(fs.readdir)
const { RecursiveCopyException } = require('../errors/RecursiveCopyException')
const PARALLEL_TASKS = 5

class FolderCopier {
  constructor (src, dest) {
    this.src = src
    this.dest = dest
  }

  async copy () {
    if (this.isDestinationSubFolderOfSource()) {
      const msg = `cannot copy '${this.src}' to a subdirectory of itself, '${this.dest}'.`
      throw new RecursiveCopyException(msg)
    }
    return this.copyDir()
  }

  isDestinationSubFolderOfSource () {
    const sourceDirectoryName = path.dirname(this.src)
    const pathSeparator = path.sep
    const destinationBaseFolder = this.dest.split(`${sourceDirectoryName}${pathSeparator}`).pop()
    if (!destinationBaseFolder) {
      return false
    }
    const destBasename = destinationBaseFolder.split(pathSeparator).shift()
    if (!destBasename) {
      return false
    }
    const sourceBasename = path.basename(this.src)
    const areTheSame = this.src === this.dest
    const isIncluded = this.dest.includes(this.src)
    return !areTheSame && isIncluded && destBasename === sourceBasename
  }

  async copyDir () {
    const items = await readDir(this.src)
    const promises = items.map(async item => {
      const isDirectory = await new FileStat(path.join(this.src, item)).isDirectory()
      return { isDirectory, item }
    })
    const results = await Promise.all(promises)
    const files = results.reduce((acc, result) => {
      if (!result.isDirectory) {
        acc.push(result.item)
      }
      return acc
    }, [])
    return this.copyDirItems(files)
  }

  copyDirItems (items) {
    const taskQueue = new TaskQueue({ parallelTasks: PARALLEL_TASKS })
    const promises = []
    for (const item of items) {
      const promise = new Promise((resolve, reject) => {
        const src = path.join(this.src, item)
        const dest = path.join(this.dest, item)
        const task = () => new FileCopier(src, dest).copy().then(resolve, reject)
        taskQueue.pushTask(task)
      })
      promises.push(promise)
    }
    return Promise.all(promises)
  }
}

module.exports = {
  FolderCopier
}