Skip to main content

​
Overview

wreq-js can emit structured native request lifecycle events through onRequestEvent and can attach an optional diagnostics payload to the final Response when captureDiagnostics is enabled. Use this when you need to:
  • render transport-phase progress such as connecting, waiting, and loading
  • observe native download progress without consuming response.body first
  • capture timing, address, or TLS peer details for debugging

​
Enable request events

import { fetch } from 'wreq-js';

const response = await fetch('https://example.com/file.zip', {
  browser: 'chrome_142',
  onRequestEvent(event) {
    console.log(event.type, event);
  },
});

console.log(response.status);

​
Event types

EventMeaningCommon fields
request_startRequest has started in the native layer.timestamp, url
request_sentRequest has been sent and the client is waiting for a response.timestamp, url
response_headersResponse headers have arrived.timestamp, status, contentLength, url
body_progressMore response bytes were downloaded.timestamp, downloadedBytes, contentLength, url
body_completeResponse body download finished.timestamp, contentLength, url
doneNative request lifecycle completed successfully.timestamp, status, url
errorNative request lifecycle failed.timestamp, message, url

​
Progress example

const response = await fetch('https://example.com/file.zip', {
  browser: 'chrome_142',
  onRequestEvent(event) {
    switch (event.type) {
      case 'request_start':
        console.log('connecting');
        break;
      case 'request_sent':
        console.log('waiting');
        break;
      case 'response_headers':
        console.log('status:', event.status);
        break;
      case 'body_progress':
        if (event.contentLength) {
          const downloaded = event.downloadedBytes ?? 0;
          const pct = (downloaded / event.contentLength) * 100;
          console.log(`loading ${pct.toFixed(1)}%`);
        }
        break;
      case 'body_complete':
        console.log('download complete');
        break;
      case 'error':
        console.error(event.message);
        break;
    }
  },
});

console.log(await response.arrayBuffer());

​
Enable diagnostics

const response = await fetch('https://example.com', {
  browser: 'chrome_142',
  captureDiagnostics: true,
});

console.log(response.diagnostics);
When available, response.diagnostics may include:
  • totalDurationMs
  • headersDurationMs
  • status
  • localAddr
  • remoteAddr
  • tlsPeerCertificatePresent
  • tlsPeerCertificateChainLength

​
Session and transport defaults

You can enable diagnostics by default on a session or transport: 
import { createSession, createTransport } from 'wreq-js';

const session = await createSession({
  browser: 'chrome_142',
  captureDiagnostics: true,
});

const transport = await createTransport({
  proxy: 'http://proxy.example.com:8080',
  captureDiagnostics: true,
});
onRequestEvent remains a per-request callback, so you still pass it to fetch() or session.fetch() for the specific requests you want to observe.

​
Notes

  • Request events come from the native layer and reflect transport lifecycle phases, not application-level parsing.
  • body_progress is emitted during native download. You can still consume response.body, response.text(), response.json(), and the other body helpers normally.
  • Diagnostics are optional and may vary by platform or native support level.