askirmas / postcss-d-ts

import {promisify} from "util"

import {createReadStream, open, writeFile, close } from 'fs'

import {createInterface} from 'readline'

import { $exists } from "./utils"

const $open = promisify(open)

, $write = promisify(writeFile)

, $close = promisify(close)

export = rewrite

async function rewrite(filename: string, lines: string[], eol: string, checkMode: boolean) {

  const {length} = lines

  , fileExists = await $exists(filename)

  if (fileExists) {

    const lineReader = createInterface({

      input: createReadStream(filename),

      crlfDelay: Infinity,

      historySize: 0

    })

    let isSame = true

    , row = 0

    for await (const line of lineReader) {

      if (line !== lines[row]) {

        isSame = false

        break

      }

      row++

    }

    lineReader.close()

    if (isSame) {

      if (lines[row] === "")

        row++

      if (length === row)

        return

    }

  }

  if (checkMode)

    throw Error(`Content of "${filename}" should be another`)

  const fd = await $open(filename, "w")

  for (let i = 0; i < length; i++)

    await $write(fd, `${

      i ? eol : ''

    }${

      lines[i]

    }`)

  await $close(fd)

}