Attribute: source

The source attribute is used with the key attribute to specify where the data for a metric will come from.

The following table explains the possible values for the source attribute.

Source	Key (usage)	Wiki Link
dom	css selector	Source: dom
expression	expression to be processed	Source: expression
query	name of query parameter	Source: query
cookie	cookie name	Source: cookie
localStorage	localStorage key	Source: localStorage
sessionStorage	sessionStorage key	Source: sessionStorage
extension	name of extension	Source: extention
on-async	expression to async function	This is deprecated "expression" should be used instead

Examples

DOM

{
  "source": "dom",
  "key": "button",
  "action": "event",
  "on": "click",
  "tag": "button.clicked"
}

Expression

{
  "source": "expression",
  "key": "window.data.productName",
  "action": "bind",
  "tag": "product.name"
}

Query

{
  "source": "query",
  "key": "utm_source",
  "action": "bind",
  "tag": "campaign.source"
}

localStorage

{
 "source": "localStorage",
 "key": "logged-in",
 "action": "bind",
 "type": "boolean",
 "tag": "user.logged-in"
}