Ext.data.Model frequently used Fields or Mixins

[stildalf]

Hi All,

Any of you have recommendations or best practice for code re-use on frequently (but not universally) used fields in data models?

I'm aware that common fields can be placed in a base model and then used in extended models, but that's often overly simplistic - what if only a few of the extended models require a certain set of fields.

I thought of using mixins to the Ext.data.Model, but can't seem to push the additional field definitions in time:

Ext.define('MyApp.models.MixZ', {
    extend: 'Ext.Mixin',
    mixinConfig: {
        before: {
            constructor: 'addFields'
        }
    },
    addFields: function(){
        Ext.Array.push(this.fields, ['mixFieldZ1', 'mixFieldZ2']);
    }
});

Ext.define('MyApp.models.ModelA', {
    extend: 'Ext.data.Model',
    mixins: {
        mixZ: 'MyApp.models.MixZ'
    },

    fields: [ 'field1', 'field2']
});

Any suggestions?

[tristan.lee]

I'm not sure if the mixin is the best way to go. Maybe others can provide their input on that though. It seems to me having your model extend a class with these additional fields would be the easiest. It doesn't need to be a base model that all models extend. Just something specific to these few that require it.

[stildalf]

My problem with extending is the forced linear heritage. Where in the tree do I place certain fields that are selectively required across various branches?

With some more fiddling from my previous example, I think I've kludged something together that works in my simple tests so far. Allows multiple mixins per model.

Ext.define('MyApp.models.MixZ', {
    extend: 'Ext.Mixin',
    mixinConfig: {
        before: {
            constructor: 'addMixFields'
        }
    },
    addMixFields: function(){
        var fields = ['mixField1', 'mixField2'];
        Ext.Array.push(this.self.fields, fields);
        this.self.addFields(fields);
    }
});

Ext.define('MyApp.models.ModelA', {
    extend: 'Ext.data.Model',
    mixins: {
        mixZ: 'MyApp.models.MixZ'
    },

    fields: [ 'field1', 'field2']
}); 

I certainly don't know if this is the best way of doing multiple 'inheritance' for data models though?

[kleins]

In case anyone stumbles across this: I found another solution. Advantages, to my mind, are that it's simpler and that the model to be mixed in remains an ordinary model class that can be instantiated on its own, too.

Ext.define('MyApp.models.MixZ', {
    extend: 'Ext.data.Model',
    fields: ['mixField1', 'mixField2']
});

Ext.define('MyApp.models.ModelA', {
    extend: 'Ext.data.Model',
    fields: [ 'field1', 'field2']
}, function() {
    this.addFields(MyApp.models.MixZ.fields)
}); 

[stildalf]

Definitely looks more elegant than the Mixin solution, thanks for sharing despite the relevant age of the thread.