Question

Let’s say I have something like this in Knockoutjs

<pre data-bind="text: ko.toJSON($data, null, 2)">
{
    "people":[
        {
            "name":"Thor",
            "meta":[]
        },
        {
            "name":"Hulk",
            "meta":[]
        }
    ]
}
</pre>

Javascript would be something like this:

function SuperheroViewModel() {
    var self = this;
    self.people = ko.observableArray();
    self.people.meta = ko.observableArray();

    self.people.push(new Person({name: 'Thor'}));
    //self.people.push(new Person({name: 'Hulk'}));

    self.addHero= function() {
        self.people.push(
            new Person({
                name: 'Wolverine'
            })
        );

        //self.meta.push(new Meta({sex: 'male'});
    }
}

ko.applyBindings(new SuperheroViewModel());
​

HTML

<button data-bind="click: addHero">Add Hero With Meta</button>

Is it possible to add a “meta” under “Thor” or “Hulk”?

I would first like to add the “meta” when a new parent item is inserted. The second step would be adding a meta to a target “hero”.

Answer 1

If you are calling addMeta from within the context of a person, then KO will pass the current data item as the first argument to your function.

So, you would be able to call item.meta.push from within your handler.