JSONBrotliAdapter for lowdb

json-brotli-adapter.mjs

import zlib from 'zlib'
import fs from 'fs'

class JSONBrotliAdapter {
  constructor(filename) {
    this.filename = filename
  }

  async read() {
    let compressedData = null
    try {
      compressedData = await fs.promises.readFile(this.filename)
    } catch (err) {
      if (err.code === 'ENOENT') {
        return null
      }
      throw err
    }
    const uncompressedData = await new Promise((resolve, reject) => {
      zlib.brotliDecompress(compressedData, (err, result) => {
        if (err) {
          return reject(err)
        }
        resolve(result)
      })
    })
    return JSON.parse(uncompressedData.toString())
  }

  async write(data) {
    const uncompressedData = Buffer.from(JSON.stringify(data))
    const compressedData = await new Promise((resolve, reject) => {
      zlib.brotliCompress(uncompressedData, (err, result) => {
        if (err) {
          return reject(err)
        }
        resolve(result)
      })
    })
    await fs.promises.writeFile(this.filename, compressedData)
  }
}

export default JSONBrotliAdapter