[FEATURE] override attribute bindings

[miguelcobain]

Adds attribute binding override support.
Related with #10176.

Is there something missing? This is my first contribution attempt. :)

Maybe we should do something similar for classNameBindings.
I could make this override behaviour more abstract, but that would require to loop the attribute array again.
This way we only loop it once.

Should I wrap this behing a feature flag?

[miguelcobain]

Should I only test this if Ember.FEATURES.isEnabled("feature-name") is true?
If so, which feature name should I use?

[miguelcobain]

Just seen PR #10186.

Maybe normalizing attribute bindings externally (outside _applyAttributeBindings) would be better. (Wouldn't conflict with @mixonic work).

[miguelcobain]

Idea:

Call this function (wrapped in an ember feature flag) before _applyAttributeBindings.

  _normalizeAttributeBindings: function(attributeBindings){
    var attributeHash = {};

    for (var i = attributeBindings.length-1; i >= 0; i--) {
      var binding = attributeBindings[i];
      var split = binding.split(':');
      var property = split[0];
      var attributeName = split[1] || property;

      if (!attributeHash.hasOwnProperty(attributeName)) {
        //this attribute wasn't overriden, so it's safe to process it
        //add to hash to know wether or not we processed it later
        attributeHash[attributeName] = property;
      } else {
        //overriden attribute binding, remove it
        attributeBindings.splice(i, 1);
      }
    }
  },

[wagenet]

@miguelcobain for reference, any changes to the public API should be wrapped in a feature flag.

[miguelcobain]

Is this feature considered a change in the public API?
People would use attributeBindings like they always did.

[wagenet]

@miguelcobain it introduces a behavior change to the API, no? (By change, I don't mean a breaking change, I just mean that it can now do something differently than it did before.)

[miguelcobain]

Agreed. On it.

A qua, 21/01/2015, 22:37, Peter Wagenet notifications@github.com escreveu:

@miguelcobain https://github.com/miguelcobain it introduces a behavior
change to the API, no? (By change, I don't mean a breaking change, I just
mean that it can now do something differently than it did before.)

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#10213 (comment).

[miguelcobain]

Well, I just added the test with no changes to the views. Tests are passing! 😕
Does this mean that this was implemented meanwhile?

[rwjblue]

@miguelcobain - The attributeBinding system was just completely replaced on master (in #10186), so it is possible that it "just works". If you squash your commits for just the tests, I'd be happy to merge this in.

[miguelcobain]

@rwjblue Great! I think this is ready be merged.

[rwjblue]

Awesome, thanks!