Tracker Callbacks
If you call snowplow
with a function as the argument, the function will be executed when sp.js loads:
snowplow(function () {
console.log("sp.js has loaded");
});
Or equivalently:
snowplow(function (x) {
console.log(x);
}, "sp.js has loaded");
The callback you provide is executed as a method on the internal trackerDictionary
object. This means that you can access the trackerDictionary
using this
.
// Configure a tracker instance named "sp"
snowplow('newTracker', 'sp', '{{COLLECTOR_URL}', {
appId: 'snowplowExampleApp'
});
// Access the tracker instance inside a callback
snowplow(function () {
var sp = this.sp;
var domainUserId = sp.getDomainUserId();
console.log(domainUserId);
})
The callback function should not be a method:
// TypeError: Illegal invocation
snowplow(console.log, "sp.js has loaded");
This will not work because the value of this
in the console.log
function will be the trackerDictionary
rather than console
.
You can get around this problem using Function.prototoype.bind
as follows:
snowplow(console.log.bind(console), "sp.js has loaded");
For more on execution context in JavaScript, see the MDN page.
Methods which can be used from within a callback
getDomainUserId
The getDomainUserId
method returns the user ID stored in the first-party cookie:
// Access the tracker instance inside a callback
snowplow(function () {
var sp = this.sp;
var domainUserId = sp.getDomainUserId();
console.log(domainUserId);
})
getDomainUserInfo
The getDomainUserInfo
method returns all the information stored in first-party cookie in an array:
// Access the tracker instance inside a callback
snowplow(function () {
var sp = this.sp;
var domainUserInfo = sp.getDomainUserInfo();
console.log(domainUserInfo);
})
The domainUserInfo
variable will contain an array with 11 elements:
- A string set to
'1'
if this is the user's first session and'0'
otherwise - The domain user ID
- The timestamp at which the cookie was created
- The number of times the user has visited the site
- The timestamp for the current visit
- The timestamp of the last visit
- The session id
- ID of the previous session (since version 3.5)
- ID of the first event in the current session (since version 3.5)
- Device created timestamp of the first event in the current session (since version 3.5)
- Index of the last event in the session (used to inspect order of events) (since version 3.5)
getUserId
The getUserId
method returns the user ID which you configured using setUserId()
:
// Access the tracker instance inside a callback
snowplow(function () {
var sp = this.sp;
var userId = sp.getUserId();
console.log(userId);
})
getCookieName
The getCookieName
method returns the complete cookie name for the domain or session cookie:
// Access the tracker instance inside a callback
snowplow(function () {
var sp = this.sp;
var cookieName = sp.getCookieName('id');
console.log(cookieName);
})
The argument corresponds to the basename of the cookie: 'id' for the domain cookie, 'ses' for the session cookie.
getPageViewId
The getPageViewId
method returns the page view id:
// Access the tracker instance inside a callback
snowplow(function () {
var sp = this.sp;
var pageViewId = sp.getPageViewId();
console.log(pageViewId);
})