javascript - Update subviews from Ember.View

Question

I'm doing an ajax form with a server API calls. The server can returns errors messages for specific fields (example: url => 'This url is incorrect').

So I've created a specific view for my form Textfield :

(textfield.handlebars)
{{view Ember.TextField valueBinding="value"}}
{{#if hasError}}
    <div class="error">{{errorMessage}}</div>
{{/if}}

(textfield.js)
App.TextField = Ember.View.extend({
    hasError: false,
    errorMessage: "",
    templateName:     "textfield",
});

And In my form view template I have:

(form.handlebars)
<div class="form-row">
    <div class="form-element"><div class="input-wrapper">{{view App.TextField valueBinding="skill.job"}}</div></div>
</div>

(new.js)
submit: function() {
    var skill = this.get("skill");

    skill.saveResource()
    .fail( function(e) {
        //how could I set the errorMessage in my App.TextField
    });
}

When the user click on the submit button, I'm sending all form datas to the server and retrieving errors messages.

My question is how can I do to update the "subview" App.TextField to set the error messages ?

Answer 1

You could use a custom App.Error object which holds the error messages. Also, if you are planning to use ember-data there is a discussion about validation https://github.com/emberjs/data/pull/130. And there's a validation extension in the excellent Ember.js addons: https://github.com/capitainetrain/ember-addons/tree/master/packages/ember-validators/lib.

Here's what I have in mind, see http://jsfiddle.net/pangratz666/kQJ2t/:

Handlebars:

<script type="text/x-handlebars" data-template-name="edit" >
    name: {{view App.TextField valueBinding="content.name" propertyName="name" }}</br>
    age: {{view App.TextField valueBinding="content.age" propertyName="age" }}</br>
    <button {{action "save"}}>save</button>
</script>​

JavaScript:

App.Error = Ember.Object.extend({
    isError: function(propertyName) {
        return !Ember.empty(this.getErrorMessage(propertyName));
    },
    getErrorMessage: function(propertyName) {
        return this.get(propertyName);
    }
});

App.ErrorMixin = Ember.Mixin.create({
    classNameBindings: ['isError:error'],
    errorBinding: 'parentView.error',

    template: Ember.Handlebars.compile('{{#if isError}}{{errorMessage}}{{/if}}'),

    isError: function() {
        var error = this.get('error');
        return error && error.isError(this.get('propertyName'));
    }.property('error', 'propertyName'),

    errorMessage: function() {
        var error = this.get('error');
        if (error) {
            var propertyName = this.get('propertyName');
            return error.getErrorMessage(propertyName);
        }
    }.property('error', 'propertyName')
});

App.TextField = Ember.TextField.extend(App.ErrorMixin);

The error object is then constructed like this:

Ember.View.create({
    templateName: 'edit',
    contentBinding: 'App.obj',
    save: function() {
        var content = this.get('content');
        var error = this.get('error');
        if (error) {
            error.destroy();
        }

        error = App.Error.create();

        if (content.get('age') <= 100) {
            error.set('age', 'sorry, you are not wise enough');
        }

        if ('Chuck Norris' === content.get('name')) {
            error.set('name', 'yeah, and i am the queen of england');
        }

        this.set('error', error);
    }
}).append();​

Answer 2

On form.handlebars set an id for it manually (so it will override the one that ember generates automatically):

<div class="form-row">
  <div class="form-element"><div class="input-wrapper">{{view App.TextField id="skill_job" valueBinding="skill.job"}}</div></div>
</div>

And then:

submit: function() {
    var skill = this.get("skill");

    skill.saveResource()
    .fail( function(e) {
        Ember.View.views["skill_job"].set('errorMessage', 'blah');
        Ember.View.views["skill_job"].set('hasError', true);
        // of course you will probably want to handle this message from the request or whatever, hope you get the idea
    });
}