gistfile1.js

var Foo = SC.Object.extend({
    values: []
});

var bar1 = Foo.create();
bar1.get('values').push("One");
bar1.get('values').push("Two");
bar1.get('values').push("Three");

console.log(bar1.get('values'));
// output : ["One", "Two", "Three"]

var bar2 = Foo.create();
console.log(bar2.get('values'));
// output : ["One", "Two", "Three"]