Allow for usage of snowplow callback without this

[greg-el]

This PR allows for the snowplow(function() {}) callback to get tracker information without requiring the this keyword, which is useful in environments that don't support the keyword (GTM) and is a non-breaking change.

The callback has been updated to pass the tracker dictionary (the object that is referred to by this) as the last argument. This allows for it to be used as a simple replacement for this, like so:

snowplow(function (trackers) {
    var sp = trackers.sp;
    var domainUserId = sp.getDomainUserId();
});

As it is the last parameter, it still allows for the passing of arguments in the snowplow function:

snowplow(function(a, b, trackers) {
    console.log(a, b); // 1, 2
    var sp = trackers.sp;
    var domainUserId = sp.getDomainUserId();
}, 1, 2);

The this keyword is still supported in conjunction with the parameter:

snowplow(function(trackers) {
  trackers.sp.getDomainUserId() === this.sp.getDomainUserId() // true
});

[bundlemon]

BundleMon

Files added (6)

Status	Path	Size	Limits
✅	trackers/javascript-tracker/dist/sp.js	+24.56KB	30KB / +10%
✅	libraries/browser-tracker-core/dist/index.mod ule.js	+23.59KB	25KB / +10%
✅	libraries/tracker-core/dist/index.module.js	+19.5KB	20KB / +10%
✅	trackers/browser-tracker/dist/index.umd.min.j s	+17.44KB	20KB / +10%
✅	trackers/javascript-tracker/dist/sp.lite.js	+17.41KB	20KB / +10%
✅	trackers/browser-tracker/dist/index.module.js	+3.49KB	5KB / +10%

Total files change +105.99KB 0%

Final result: ✅

View report in BundleMon website ➡️

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Current branch size history

[jethron]

LGTM if LGT @matus-tomlein

[matus-tomlein]

LGTM!