MooTool's String.prototype.contains conflicts with ES6

[benjaminp]

ES6 adds the String.prototype.contains method (specified here; look at the PDF). As you can see, it does not have the same behavior as MooTools' String.prototype.contains. Namely, the second parameter in ES6 is a position to start searching from not a separator. Firefox 17 implements the ES6 version, which is breaking sites that use MooTools.

[arian]

Only MooTools 1.2 breaks. MooTools >= 1.3 overwrites .contains because it's not in this list: https://github.com/mootools/mootools-core/blob/c7a161d85/Source/Core/Core.js#L266-268

That said, we probably should prepare for those new methods and make our API compatible in 1.4.6 and 1.5.

@gutworth what's the current status? As far as I know it's only a proposal, but now it's implemented it probably won't change a lot, will it?
Also, what other new methods can we expect, I saw the string extras, Array.from/Array.of, and some number methods right?

[benjaminp]

There are more methods on the Number constructor: Number.isFinite(), Number.isInteger(), Number.isNaN(), Number.toInteger().

Technically, everything is subject to change until the spec is finalized. However, the new methods in Firefox are based on the harmony proposals page, which is supposed to mean the committee has reached consensus even if it's not formally speced yet.

[sebmarkbage]

There is some chance there might be Object.extend and more as well.

[BenoitZugmeyer]

Note for completeness: Mozilla care about this issue and apparently will do some evangelism in order to prevent websites using MooTools 1.2 to break when Firefox 17 will be released.

See comment https://bugzilla.mozilla.org/show_bug.cgi?id=784280#c10

[arian]

That's great to hear. I do think we should change String.prototype.contains to match the signature with ES6 though in 1.5.

[DavidBruant]

I've added a section on MDN to describe this issue. Please tell me if I've made a mistake.

I agree it would make sense for MooTools to match ES6 signature. However, the feature isn't exactly the same, namely on the second parameter.
So, one thing that would ease the transition from MooTools 1.2 to 1.5 would be to provide an alias for the current String.prototype.contains (maybe to String.prototype.legacyContains or String.prototype.oldContains). This way, people using the old version will just have to rename their calls and not the logic around it.

[sebmarkbage]

We did end up changing method signature for bind and had a tutorial for upgrading: https://github.com/mootools/mootools-core/wiki/Update-from-1.2-to-1.3
We already had a suitable alternative.

There was some projects that couldn't update to 1.3 for a long time, for various reasons (most notably Joomla). So there was also a minor revision update 1.2.5. For whatever reason that version only fixed bind specifically. Not the real issue. It wasn't until 1.3 all native methods were overridden. Maybe there needs to be a 1.2.6 release to allow for a quick fix.

[arian]

Needs a fix for MooTools 1.2.6, as it probably breaks some selectors ($$) too: https://groups.google.com/forum/#!topic/mootools-users/W7MHwTFHYQ4

[Enyby]

Quick fix: You need add "String.prototype.contains = undefined;" before init mootools core. Or add this row as first row in your core file.
Note: You need check other js code for using String.prototype.contains in default way. But this function implement only in firefox, than its usage unlikely.

[hnuecke]

Danke! Die Zeile in mootools core einzufügen war auch für mich (2.9.5) die Lösung

[arian]

Okay, this problem is solved for 1.2 now too, and released, so we can close this! http://mootools.net/blog/2013/02/19/mootools-1-2-6-released/