Function transform

packages/server-renderer/__tests__/render.spec.ts:54–57

(data, _encoding, cb)

const pipeToWritable = (app: any, context?: any) => {
  const stream = new Transform({
    transform(data, _encoding, cb) {
      this.push(data)
      cb()
    },
  })
  pipeToNodeWritable(app, context, stream)
  return promisifyStream(stream)