In Custom property, how can I define the utm_medium is not set

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To define that the utm_medium is not set in a Custom Property in Mixpanel, you can use the undefined constant. Here's how you can do it:1. Create a new Custom Property 2. In the property definition, use the undefined constant to check if utm_medium is not setThe logic would look something like this:LBKSif(event.properties.utm_medium == undefined)LBKSThis condition checks if the utm_medium property is undefined, which is equivalent to it not being set.It's important to note that in Mixpanel, there's a distinction between undefined and (not set):- undefined refers to cases where a property value has not been defined or set at all. - (not set) refers to events where a property value has not been set during tracking or ingestion Mixpanel Documentation.So, by using undefined in your Custom Property definition, you're specifically targeting cases where utm_medium has not been defined or set at all.Remember that Mixpanel automatically tracks UTM parameters, including utm_medium, when using their JavaScript SDK Mixpanel Documentation. If you're not seeing utm_medium values, make sure you're correctly implementing UTM parameter tracking in your setup.

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To check if the utm_medium is specifically (not set) in a Custom Property in Mixpanel, you would use a different approach than checking for undefined. Here's how you can do it:1. Create a new Custom Property 2. In the property definition, use a condition to check if utm_medium is equal to (not set)The logic would look something like this:LBKSif(event.properties.utm_medium == "(not set)")LBKSThis condition checks if the utm_medium property is exactly equal to the string "(not set)".It's important to understand the distinction between undefined, null, and (not set) in Mixpanel:- undefined refers to cases where a property has not been defined at all. - null represents the intentional absence of any object value. - (not set) refers to events where a property value has not been set during tracking or ingestion.According to the Mixpanel documentation, both null values and undefined values are parsed as (not set) in the UI. However, when looking at raw data, null values may appear as <null> or null.When working with UTM parameters, it's worth noting that Mixpanel's JavaScript SDK automatically tracks these parameters Mixpanel Documentation. If you're seeing (not set) values for utm_medium, it likely means that the parameter was not present in the URL when the user arrived at your site.Remember, if you want to analyze cases where UTM parameters are not set, you might also want to consider using Mixpanel's Custom Buckets feature, which allows you to group values like (not set) into meaningful segments for your analysis.

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