JavaScript SDK FAQs

Solutions to some of the commonly faced issues while using the RudderStack JavaScript SDK.

This guide contains the answers to some of the commonly-asked questions around setting up, using, and troubleshooting the RudderStack JavaScript SDK.

For queries or issues not listed in this guide, you can always start a conversation on our Slack channel.

Where do I get the data plane URL?

For routing and processing the events to the RudderStack backend, a data plane URL is required. Refer to this section to get the data plane URL depending on your choice of setup.

How do I load the SDK (rudder-analytics.js) correctly?

To load rudder-analytics.js, follow the instructions in the Install RudderStack JavaScript SDK section.

To check if the library has loaded correctly, open the JavaScript console in your browser:

• Safari: Ctrl+Alt+I (Windows) or Command+Option+I (Mac) and go to the Console tab.

• Chrome: Ctrl+Shift+J (Windows) or Command+Option+J (Mac).

• Firefox: Ctrl+Shift+K (Windows) or Command+Option+K (Mac) and select the Console tab.

• Internet Explorer: Press F12 and go to the Console tab.

In the console, run rudderanalytics. If it returns an object as shown in the following code snippet, it means that the rudder-analytics.js file has loaded successfully:

{Integrations: Object, _integrations: Object, _readied: true, _timeout: 300, _user: n_}

If it gives you an undefined error, verify if the installation is done correctly. Our quick start guide may be able to help you get up and running.

Should I disable ad-blockers on my browser?

Yes, it is important that you ensure no ad blockers are running on your browser, as they restrict therudder-analytics.js script from executing and storing user information in the browser.

Can I load multiple instances of rudder-analytics.js?

No, it is not possible to load multiple instances of rudder-analytics.js, as it is bound to exceed the maximum stack call size and give you an error.

How to check if the data is being transmitted to the desired destinations?

To check if data is being transmitted to the specified destinations, go to the Network tab of your JavaScript console in your browser.

If the outbound request is not shown, check if you have installed and set up the RudderStack JavaScript SDK correctly. Also, check if any ad blockers are enabled in your browser.

What is the size limit on the requests?

The size limit on requests is 32KB per message and 4MB per batch request.

Can I send the event data to specific destinations only?

Yes, you can follow any one of the following methods to send your event data to specific destinations:

• Sending events to selective destinations: You can send your events only to the selective destinations by stopping the SDK from loading the other device modeintegrations.

• Filtering out selective destinations: With this approach, you can stop RudderStack from delivering certain events to the specified destinations.

What is an anonymous ID? How do I retrieve it?

An anonymous ID is an auto-generated UUID (Universally Unique Identifier) that gets assigned to each unique, unidentified visitor to your website.

To retrieve the anonymous ID of any visitor, call the following:

rudderanalytics.getAnonymousId();

If the anonymousId value is null in the SDK, calling the above function will lead to RudderStack automatically setting a new anonymousId.

What is the Reserved Keyword error?

When using the JavaScript SDK, you may run into the following error: Warning! : Reserved keyword used in traits --> id with track call. This is because one or more of the keys in your traits and/or properties object is the same value as a reserved keyword.

RudderStack has reserved the following keywords as keys for a standard event payload:

"anonymous_id";
"id";
"sent_at";
"received_at";
"timestamp";
"original_timestamp";
"event_text";
"event";

The above-mentioned keywords should be avoided when naming your event traits and properties.

Contact us

For more information on the RudderStack JavaScript SDK, you can contact us or start a conversation in our Slack community.

If you come across any issues while using this SDK, feel free to submit them on our GitHub issues page.