@magic/core/src/tasks/watch/index.mjs

@magic core. generate static pages and serverless lambdas. ~5kb client boilerplate.

import path from 'path'

import is from '@magic/types'
import fs from '@magic/fs'

const onFileChange =
  dir =>
  (evt, file = '') => {
    if (!is.string(file)) {
      file = ''
    }

    const filePath = path.join(dir, file)
    if (!is.str(evt)) {
      evt = 'change'
    }

    process.send({ evt, file: filePath })
  }

const watchListener = async src => {
  const stat = await fs.stat(src)

  if (stat.isDirectory(src)) {
    fs.watch(src, onFileChange(src))

    const subDirs = await fs.getDirectories(src, { depth: 1 })
    const promises = subDirs.filter(dir => dir !== src).map(watchListener)

    await Promise.all(promises)
  } else if (stat.isFile(src)) {
    fs.watchFile(src, onFileChange(src))
  }
}

export const watch = async files => await Promise.all(files.map(watchListener))

export default watch