Returns

{Array}:

An array of enumerable key strings on the object.

var shapeless = {};

// Nothing enumerable in a shapeless object
shapeless[canSymbol.for('can.getOwnEnumerableKeys')] = function() { return []; }

var thingsInMyEar = {};
Object.defineProperty(thingsInMyEar, "banana", {
    enumerable: false,
    value: {
        peeled: false
    }
});

thingsInMyEar[canSymbol('can.getOwnEnumerableKeys')] = function() { 
    return Object.getOwnPropertyNames(this).filter(function(key) { 
        return !!Object.getOwnPropertyDescriptor(this, key).enumerable 
    }.bind(this))
    .concat(["banana"]);  // There's always a banana in my ear
};