Function sendCachedValue

lib/interceptor/cache.js:177–252

* @param {import('../../types/dispatcher.d.ts').default.DispatchHandler} handler * @param {import('../../types/dispatcher.d.ts').default.RequestOptions} opts * @param {import('../../types/cache-interceptor.d.ts').default.GetResult} result * @param {number} age * @param {any} context * @param {b

(handler, opts, result, age, context, isStale)

 * @param {boolean} isStale
 */
function sendCachedValue (handler, opts, result, age, context, isStale) {
  // TODO (perf): Readable.from path can be optimized...
  const stream = util.isStream(result.body)
    ? result.body
    : Readable.from(result.body ?? [])

  assert(!stream.destroyed, 'stream should not be destroyed')
  assert(!stream.readableDidRead, 'stream should not be readableDidRead')

  const controller = {
    rawHeaders: [],
    rawTrailers: [],
    resume () {
      stream.resume()
    },
    pause () {
      stream.pause()
    },
    get paused () {
      return stream.isPaused()
    },
    get aborted () {
      return stream.destroyed
    },
    get reason () {
      return stream.errored
    },
    abort (reason) {
      stream.destroy(reason ?? new AbortError())
    }
  }

  stream
    .on('error', function (err) {
      if (!this.readableEnded) {
        if (typeof handler.onResponseError === 'function') {
          handler.onResponseError(controller, err)
        } else {
          throw err
        }
      }
    })
    .on('close', function () {
      if (!this.errored) {
        handler.onResponseEnd?.(controller, {})
      }
    })

  handler.onRequestStart?.(controller, context)

  if (stream.destroyed) {
    return
  }

  // Add the age header
  // https://www.rfc-editor.org/rfc/rfc9111.html#name-age
  const headers = { ...result.headers, age: String(age) }