Implementation:Nightwatchjs Nightwatch CreateClient And LaunchBrowser

Knowledge Sources	Nightwatch Nightwatch Programmatic API
Domains	Testing, API, Session_Management
Last Updated	2026-02-12 00:00 GMT

Overview

Concrete API for creating a Nightwatch client and launching a browser session via createClient() and launchBrowser().

Description

Nightwatch.createClient(options) returns a client wrapper object with launchBrowser(), updateCapabilities(), settings, cleanup(), runGlobalBeforeHook(), and runGlobalAfterHook() methods. Calling launchBrowser({ loadNightwatchApis: true }) initializes the internal client, creates a WebDriver session, and returns a Promise resolving to the browser (NightwatchAPI) instance.

Usage

Call createClient() with options, optionally update capabilities, then call launchBrowser() to get the browser instance. Always call cleanup() when done.

Code Reference

Source Location

Repository: nightwatch
File: lib/index.js (lines 34-204)

Signature

// Step 1: Create client
const client = Nightwatch.createClient(options);

// ClientWrapper interface:
client.launchBrowser(opts?: { loadNightwatchApis?: boolean }) -> Promise<NightwatchAPI>
client.updateCapabilities(value: Object) -> void
client.settings -> Object  // Read-only settings
client.cleanup() -> Promise<void>
client.runGlobalBeforeHook() -> Promise<void>
client.runGlobalAfterHook() -> Promise<void>

// Step 2: Launch browser
const browser = await client.launchBrowser();
// browser is now a NightwatchAPI instance

Import

const Nightwatch = require('nightwatch');

I/O Contract

Inputs

Name	Type	Required	Description
options	Object	No	Configuration options (see CreateClient_Options)
loadNightwatchApis	boolean	No	Load Nightwatch API on browser object (default: true)

Outputs

Name	Type	Description
client	ClientWrapper	Object with launchBrowser, updateCapabilities, settings, cleanup
browser	NightwatchAPI	Full browser API with navigateTo, click, assert, expect, etc.

Usage Examples

Full Programmatic Lifecycle

const Nightwatch = require('nightwatch');

(async function() {
  // Step 1: Create client
  const client = Nightwatch.createClient({
    browserName: 'chrome',
    headless: true
  });

  // Optional: Update capabilities
  client.updateCapabilities({
    'goog:chromeOptions': {
      args: ['--window-size=1920,1080']
    }
  });

  // Step 2: Launch browser
  const browser = await client.launchBrowser();

  // Step 3: Use browser
  await browser.navigateTo('https://example.com');
  await browser.assert.titleContains('Example');

  // Step 4: Cleanup
  await browser.end();
  await client.cleanup();
})();

Related Pages

Implements Principle

Principle:Nightwatchjs_Nightwatch_Client_Initialization

Requires Environment

Uses Heuristic

Heuristic:Nightwatchjs_Nightwatch_Node_17_DNS_IPv4_Workaround

Page Connections

Double-click a node to navigate. Hold to expand connections.

Principle

Implementation

Heuristic

Environment