Best practice for overriding classes / properties in ExtJS?

Question

I have an Ext.form.field.Text and I want to override the setValue function.

What is the recommended way to override this class functionalit

Answer 1

The answer by @sra is great and was very helpful to me in gaining a deeper understanding of the override functionality available in Ext, but it does not include the way that I most commonly implement overrides which looks something like this:

Ext.define('my.application.form.field.Text' {
    override: 'Ext.form.field.Text'
    getValue: function () {
        // your custom functionality here
        arguments[1] = false;

        // callParent can be used if desired, or the method can be 
        // re-written without reference to the original
        this.callParent(arguments)
    }
});

I'm still using Ext 5 so I would then load this file in my Application.js and add it to the requires array there which applies the override to the app globally. I think Ext 6 projects include an override folder and simply adding this file to that folder ensures the override is applied.