NaturalCycles/nodejs-lib

import { Transform } from 'node:stream'
import { progressLogger, ProgressLoggerCfg } from '../progressLogger'
import { TransformOptions, TransformTyped } from '../stream.model'

export interface TransformLogProgressOptions<IN = any>
  extends ProgressLoggerCfg<IN>,
    TransformOptions {}

/**
 * Pass-through transform that optionally logs progress.
 */
export function transformLogProgress<IN = any>(
  opt: TransformLogProgressOptions = {},
): TransformTyped<IN, IN> {
  const progress = progressLogger(opt)

  return new Transform({
    objectMode: true,
    ...opt,
    transform(chunk: IN, _, cb) {
      progress.log(chunk)
      cb(null, chunk) // pass-through
    },
    final(cb) {
      progress.done()
      cb()
    },
  })
}