throttle

Throttle the network capabilities of the browser. This can help to emulate certain scenarios where a user loses their internet connection and your app needs to address that.

There are many presets available with default configurations for ease of use. They are offline, GPRS, Regular2G, Good2G, Regular3G, Good3G, Regular4G, DSL, WiFi, online.

You can see the values for these presets in the source code.

info

Note that using the throttle command requires support for Chrome DevTools protocol and e.g. can not be used when running automated tests in the cloud. Find out more in the Automation Protocols section.

Usage

browser.throttle({ offline, latency, downloadThroughput, uploadThroughput })

Parameters

Name	Type	Details
params	ThrottleOptions	parameters for throttling
params.offline	Boolean	True to emulate internet disconnection.
params.latency	Number	Minimum latency from request sent to response headers received (ms).
params.downloadThroughput	Number	Maximal aggregated download throughput (bytes/sec). -1 disables download throttling.
params.uploadThroughput	Number	Maximal aggregated upload throughput (bytes/sec). -1 disables upload throttling.

Example

Asynchronous Mode

throttle.js

it('should throttle the network', async () => {
    // via static string preset
    await browser.throttle('Regular 3G')

    // via custom values
    await browser.throttle({
        offline: false,
        downloadThroughput: 200 * 1024 / 8,
        uploadThroughput: 200 * 1024 / 8,
        latency: 20
    })
});

Synchronous Mode

throttle.js

it('should throttle the network', () => {
    // via static string preset
    browser.throttle('Regular 3G')

    // via custom values
    browser.throttle({
        offline: false,
        downloadThroughput: 200 * 1024 / 8,
        uploadThroughput: 200 * 1024 / 8,
        latency: 20
    })
});

caution

Synchronous Mode will depcrecated with Node.js v16. With an update to the underlying Chromium version it became technically impossible to provide the same synchronous behavior. We recommend to start transition to asynchronous command execution. For more information, see our RFC.