Cut support for IE6-8 and other older browsers.

[jdalton]

With jQuery and Dojo moving away from supporting older browsers (FF3, IE6-IE8, older Opera) I think Underscore is in a good position to drop support as well.

Devs needing older browser support can always use a compat build of Underscore or Lo-Dash (no troll), which has extensive older browser support and a build system to allow selectively supporting older/newer environments.

[lukesutton]

There are only a small set of projects where you can say support for IE6–8 isn't needed. Unless _ was going to adopt a release cycle like jQuery — parallel, API compatible versions with different support sets — it's too early to start talking about removing support. Alas.

[jdalton]

Unless _ was going to adopt a release cycle like jQuery — parallel, API compatible versions with different support sets — it's too early to start talking about removing support. Alas.

Underscore is billed as "the tie to go along with jQuery's tux" and if the tux, jQuery, drops support, it only makes sense that the tie, Underscore, should follow.

With older browser support and Underscore compatibility handled by something like Lo-Dash, Underscore is free to make the shift, simplifying its code, slimming down, and optimizing for modern browsers/environments, without worrying about back compat.

[knowtheory]

I took a moment to crunch the access logs DocumentCloud has on hand, and of the 1.8 mil hits in the logs, the IE breakdown looks like this:

      9 MSIE 4.0
     78 MSIE 5.0
     54 MSIE 5.5
   2086 MSIE 6.0
      1 MSIE 6.1
  32700 MSIE 7.0
  67311 MSIE 8.0
  80300 MSIE 9.0
   4199 MSIE 10.0
     19 MSIE 999.1

So, we're still getting 10% of traffic from IE, 5% of total traffic from IE7-8. We're getting close, but i don't feel like we're at the point yet where underscore can go >=IE9

Touched base with some of our users, and they're running between a quarter to 40% traffic from IE, half of those numbers being earlier IE9.

Dropping IE7/8 support isn't a bad idea, i'm just not convinced we should do it yet.

[jdalton]

@knowtheory Thanks for taking the time to crunch numbers! As mentioned compat support is already being provided by other projects so Underscore is free to drop its support for legacy browsers, in future versions, without having to worry about carrying the compat burden.

[lukeasrodgers]

The more I think about this, the more sense it makes, I think. Without wanting to appear overly pedantic when it comes to versioning, I would expect dropping support for legacy browsers to necessitate a version bump to 2.0.

You might make your case stronger by listing some examples of the inconsistent support for legacy browsers. I'm aware of the handling of sparse arrays but not any others off the top of my head.

[jdalton]

You might make your case stronger by listing some examples of the inconsistent support for legacy browsers. I'm aware of the handling of sparse arrays but not any others off the top of my head.

Besides sparse array inconsistencies, there are object/function/string iteration inconsistencies as well.

In IE < 9 Underscore will not iterate arguments objects as objects correctly (so in methods like _.keys and _.isEmpty) because it won't iterate over their index values, Underscore won't iterate strings as array-like values, and will skip iterating own constructor, hasOwnProperty, isPrototypeOf, propertyIsEnumerable, toLocaleString, toString, and valueOf properties of objects.

Also, Underscore will incorrectly iterate the usually non-enumerable prototype property of functions in older versions of Firefox, Opera, and Safari.

Underscore is the only mainstream lib, with older browser support, that doesn't attempt to solve any of these compatibility/consistency issues. With an alternative that does handle these older browser issues, now is a great time for Underscore to cut support.

[rwaldron]

+1

I'm not dog-piling, I'm advocating.

[sindresorhus]

👍 It's time.

[danheberden]

+1

If you'd like to stay similar to jQuery, users can always use an older version of underscore if support for IE6-8 is necessary.

[phated]

The point to use a library for some of these things is consistency with old browsers, and if underscore isn't achieving that, then let lo-dash handle it and cut the support.

[mathiasbynens]

+9001 — Let’s move the web forward. Any project even half as popular as Underscore can make a difference.

A note with a link to an older version of Underscore (or an oldIE-compatible build of Lo-Dash) could be added to the README for those who still need to support older browsers (gah — for some projects I still need to!).

[monteslu]

+9002 We'll always have people using IE8 if we keep supporting it.

[anthonyshort]

👍

[caseywebdev]

👍 to injecting code that will permanently erase IE from a user's machine

[zzolo]

We love underscore and use it on many projects. Thanks for all the great work.

We still have 20%+ of our users on IE8, while IE7 sees less than 4%. We have basically decided to fully support IE8 and loosely support IE7.

I would agree with dropping support for IE7 and definitely IE6. I would also possibly agree with dropping active support for IE8 if the gaps could be filled in with something like es5shim.

A few specific questions to ask about whether to keep support:

• What are the specific missing parts of IE6/7/8?
• What is the amount of work needed to support these browsers?
• Will someone maintain support for old browsers?
• What is the browser breakdown for the users of this library? (assuming everyone, so general stats would be good)