如何从流星视图的更改事件更新模型？

Question

I have a meteor application. It has a simple data model, and edit screen. The model is following:

{
   _id: "some_id",
   date: "date",
   attempts: [{k1: "v1"}, {k1: "v2"}, {k1: "v1"}]
}

This model is stored in session. Edit screen is organasied in the following way:

<template name="editModel">
    <form>
        {{#each model.attempts}}
            {{> attempt}}
            <hr/>
        {{/each}}
    </form>
    <button class="btn add-rep">Add</button>
    <hr/>
    <button type="submit" class="btn btn-primary submit-exercise">Submit</button>
</template>

<template name="attempt">
    <label>K1</label>
    <select name="k1">
        <option {{selected k1 "1"}} >1</option>
        <option {{selected k1 "2"}} >2</option>
    </select>
</template>

The attempt template basically is just dropdown, that should update k1 property of object. I wrote following code:

function keyChanged (e, t){
    t.data.k1 = t.find("[name='k1']").value;
}

Template.attempt.events = {
    "change select[name='grip']"    : keyChanged
}

But it does not work, because data is read only. The question is: how can I update that object inside attempts array?

Answer 1

You've not given enough detail on your collection to go on, but you would update your collection directly to change your model's data, or use what you're using as your model engine to do it.

Eg to update your collection directly (add something to that array):

Collection.update(id_of_record,{attempts : { $addToSet: {k1:"v9"} } });

So this would add a new record to the set. Have a look at all the operations possible , with the mongodb docs on arrays such as $addToSet the only thing you can't do for the moment is use the $ positional operator

As soon as you update your collection the corresponding template data would update using reactivity. I would be a bit careful and use {{#isolate}} & {{#constant}} with your use case to ensure the data around your HTML is rendered without having the entire template redraw so. See Reactivity Isolation & Constant Regions