$add problem

[butsalt]

<div id="app"></div>
<div id="app2"></div>

var Vue = require("vue");

var data = global.data = {
    foo: {
        bar: "something"
    }
};

var app = global.app = new Vue({
    data: data,
    template: "<div>{{foo.bar}}</div><div>{{foo.bao}}</div>"
}).$mount("#app");

var app2 = global.app2 = new Vue({
    data: data.foo,
    template: "<div>{{bar}}</div>"
}).$mount("#app2");

Then I invoke $add in console

data.foo.$add("bao","koo")

Nothing happened.
I think that might because data.foo has been observed as app2's root $data. So when I invoke $add, it is helpfull with app2, but it will not trigger the deps that on data.foo.

[OEvgeny]

Yes, seems not work correctly. Fiddle for this http://jsfiddle.net/Lh6h0Ly0/

[azamat-sharapov]

So app.$add('bao', 'koo') won't work for you case?

[azamat-sharapov]

Actually it should be data.$add('foo.bao', 'koo') instead of data.foo.$add('bao', 'koo').