Track Event for the JavaScript (Browser) SDK

Tracks a conversion event for a user. In other words, tracks an action a user takes. Logs an error message if the specified event key does not match any existing events. See How Optimizely Experimentation counts conversions.

Version

4.5 and higher. See Minimum version support.

Description

Use this method to track events across multiple flag rules for a user. You should make only one trackEvent call per conversion (user action), even if many rules measure the conversion.

You call the trackEvent method on a user. For information about the user object, see OptimizelyUserContext for the JavaScript (Browser) SDK.

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Important

The attributes passed to trackEvent are only used for results segmentation on the Optimizely Experiment Results page.

Parameters

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Beta

Event properties and the reserved tag key,$opt_event_properties, are currently in beta.

• eventKey (required) – String – The key of the event to be tracked. This key must match the event key provided when the event was created in the Optimizely app or REST API.
• eventTags (optional) – Map – A map of key-value pairs specifying the reserved tag keys names and their corresponding values for this particular event occurrence. eventTags are contextual metadata about conversion events. For example, revenue, load time, or total value. The following are available tag keys:
  • revenue – An integer value that is used to track the revenue metric for your experiments, aggregated across all conversion events. revenue is recorded in cents.
  • value – A floating point value that is used to track a custom value for your experiments. Use this to pass the value for numeric metrics.
  • $opt_event_properties – A map of default and custom event properties and their values.

See reserved event tags.

Returns

This method sends conversion data to Optimizely Feature Experimentation. It does not provide return values.

Example

const attributes = { logged_in: true }; 
const user = optimizely.createUserContext('user123', attributes); 
// Map of event properties
const properties = { 
  category: 'shoes', 
  color: 'red' 
}; 
//Map of eventTags
const tags = { 
  $opt_event_properties: properties,
  revenue: 10000,
  value: 100.00
}; 

// user.trackEvent(eventKey (required), eventTags (optional));
user.trackEvent("my_purchase_event_key", tags);

Side effects

Additional Feature Experimentation functionality may be triggered by using this method.

Conversions

Calling this method records a conversion and attributes it to the variations that the user has seen. See How Optimizely Experimentation counts conversions.

You can create metrics on this conversion event and add metrics to experiments even after the conversion is tracked. See Events: Tracking clicks, pageviews, and other visitor actions.

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Warning

This method does not track events if the event key is invalid.

Changing the traffic allocation of running experiments affects how conversions are recorded and variations are attributed to users. See Why you should not change a running experiment.

Notification listeners

Accessing this method triggers a call to the TRACK notification listener.

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Warning

This method does not call the TRACK notification listener if the event key is invalid.

Source files

The language and platform source files containing the implementation for the JavaScript (Browser) SDK are available on GitHub.