Update browser targets for compilation (closes #1131)

[Peter Perlepes (igneel64)]

Based on our internal data and open source information the first proposal for the v4 compilation targets is the one presented.

Highlights

• Dropping support for IE9 and IE10
• Minimum Safari is 9.1
• 'Evergreen' type browsers are bumped

Notes

• Our compiled artifacts do not seem to change after the bump.

[bundlemon]

BundleMon

Files added (6)

Status	Path	Size	Limits
✅	libraries/browser-tracker-core/dist/index.mod ule.js	+23.8KB	25KB / +10%
✅	trackers/javascript-tracker/dist/sp.js	+23.49KB	25KB / +10%
✅	trackers/javascript-tracker/dist/sp.lite.js	+14.2KB	15KB / +10%
✅	trackers/browser-tracker/dist/index.umd.min.j s	+14.05KB	15KB / +10%
✅	libraries/tracker-core/dist/index.module.js	+13.36KB	15KB / +10%
✅	trackers/browser-tracker/dist/index.module.js	+3.46KB	5KB / +10%

Total files change +92.35KB 0%

Final result: ✅

View report in BundleMon website ➡️

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Current branch size history

[Matus Tomlein (matus-tomlein)]

LGTM!

[Jack Keene (Jack-Keene)]

LGTM!

[Paul Boocock (paulboocock)]

LGTM. Out of scope for this PR, but there are a number of places where we can also now improve the code by removing IE<11.

A couple that quickly spring to mind:

• The out queue, no need for Image any more, it can all be XHR.
• Integration Tests ;-)
• Bumping UUID library to latest

I'm also a little surprised the output didn't change. The underlying library uses this file to figure out if typescript should transpile to ES3 or ES5. It always picked ES3, but I'd have thought we'd have ended up with ES5 now. I can't quite remember how, but using the TS lib we have and running it in node, you can feed this file into it and it outputs the TS version it selects.

[Peter Perlepes (igneel64)]

Paul Boocock (@paulboocock)
About ES3-ES5, even with the old settings we were in ES5 supported environments https://caniuse.com/es5 .
Did you find any hint that this compiled down to ES3 in the past ?

If we said we support ES3, we would need to polyfill methods such as Array.prototype.map, Object.keys etc. which we already use in our code.