Add contains to includes RFC

[alexspeller]

contains is implemented on Ember.Array, but contains was renamed to includes in 2014 - should contains be deprecated in favour of an includes method in ember?

Rendered

[mixonic]

@alexspeller includes would be an extension of the native array prototype, and thus should be 100% API compatible with the native implementation that will replace it when present. For example includes (MDN docs here) takes an optional fromIndex.

Basically, I suggest that includes be a polyfill for the spec'd behavior. Then contains can be deprecated. However just renaming contains -> includes is not sufficient.

[alexspeller]

@mixonic updated RFC to reflect that

[locks]

A deprecation guide also needs to get written, and since includes and contains seem to have slightly different semantics, the guide should address that with examples of how to migrate existing code.

[locks]

We might also want to indicate in the API documentation that this is a polyfill.

[alexspeller]

@locks updated based on your comments

[rwjblue]

We discussed in the core team meeting yesterday, we are 👍 on this.

[mixonic]

:-D

[bmeurant]

I think I can try to handle this if still available

One thing to confirm, it has to be implemented also in Enumerable (without fromIndex), right ? Not only in Array ?

[rwjblue]

FYI - I created https://github.com/rwjblue/ember-runtime-enumerable-includes-polyfill to make this a bit easier for addons to avoid deprecations, use the newer syntax, and continue to support older versions of Ember.