Heads Up! You're viewing the docs for v5.1, an old version of Karma. v6.4 is the newest.

Public Api

Most of the time, you will be using Karma directly from the command line. You can, however, call Karma programmatically from your node module. Here is the public API.

karma.Server(options, [callback=process.exit]) #

Constructor #

var Server = require('karma').Server
var karmaConfig = {port: 9876}
var server = new Server(karmaConfig, function(exitCode) {
  console.log('Karma has exited with ' + exitCode)

Notice the capital 'S' on require('karma').Server.

server.start() #

Equivalent of karma start.


server.refreshFiles() #

Trigger a file list refresh. Returns a promise.


server.refreshFile(path) #

Trigger a file refresh. Returns a promise.


Events #

The server object is an EventEmitter. You can simply listen to events like this:

server.on('browser_register', function (browser) {
  console.log('A new browser was registered')

listening #


  • port: Port number

Begin accepting connections on the specified port.

browser_register #


  • browser: The browser instance

A new browser was opened, but is not ready yet.

browser_error #


  • browser: The browser instance
  • error: The error that occurred

There was an error in this browser instance.

browser_start #


  • browser: The browser instance
  • info: Details about the run

A test run is beginning in this browser.

browser_complete #


  • browser: The browser instance
  • result: Test results

A test run has completed in this browser.

browsers_change #


  • browsers: A collection of browser instances

The list of browsers has changed.

browsers_ready #

All browsers are ready for execution

run_start #


  • browsers: A collection of browser instances on which tests are executed

A test run starts.

run_complete #


  • browsers: A collection of browser instances
  • results: A list of results

A test run was completed.

karma.runner #

runner.run(options, [callback=process.exit]) #

The equivalent of karma run.

var runner = require('karma').runner
runner.run({port: 9876}, function(exitCode) {
  console.log('Karma has exited with ' + exitCode)

runner.run() returns an EventEmitter which emits a progress event passing the reporter output as a Buffer object.

You may listen for that event to print the reporter output to the console:

runner.run({port: 9876}).on('progress', function(data) {

karma.stopper #

stopper.stop(options, [callback=process.exit]) #

This function will signal a running server to stop. The equivalent of karma stop.

var stopper = require('karma').stopper
stopper.stop({port: 9876}, function(exitCode) {
  if (exitCode === 0) {
    console.log('Server stop as initiated')

karma.config.parseConfig([configFilePath], [cliOptions]) #

This function will load given config file and returns a filled config object. This can be useful if you want to integrate karma into another tool and want to load the karma config while honoring the karma defaults. For example, the stryker-karma-runner uses this to load your karma configuration and use that in the stryker configuration.

const cfg = require('karma').config;
const path = require('path');
// Read karma.conf.js, but override port with 1337
const karmaConfig = cfg.parseConfig(path.resolve('./karma.conf.js'), { port: 1337 } );

karma.constants #

constants.VERSION #

The current version of karma

constants.DEFAULT_PORT #

The default port used for the karma server


The default hostname used for the karma server


The default address use for the karma server to listen on

constants.LOG_DISABLE #

The value for disabling logs

constants.LOG_ERROR #

The value for the log error level

constants.LOG_WARN #

The value for the log warn level

constants.LOG_INFO #

The value for the log info level

constants.LOG_DEBUG #

The value for the log debug level

constants.LOG_PRIORITIES #

An array of log levels in descending order, i.e. LOG_DISABLE, LOG_ERROR, LOG_WARN, LOG_INFO, and LOG_DEBUG

constants.COLOR_PATTERN #

The default color pattern for log output

constants.NO_COLOR_PATTERN #

The default pattern for log output without color


The default console appender

constants.EXIT_CODE #

The exit code

Callback function notes #

  • If there is an error, the error code will be provided as the second parameter to the error callback.