Question

I’m writing a plugin where I would need to “Bind” a parameter.
Sometimes I need the value of this.checked, but sometimes it’s $(this).val() what I need, and there are cornercases when I need to check other attributes.

I need an “input parameter” for the initialization which somehow determines what to check for the value.

I can do this with eval, but it’s evil.
I can do this with a switch case, but I’m not sure I can prepare for everything.

What is the best way to do this?

$.fn.formSwitch = function (options) {

    var settings = $.extend({
        visibleholder: '#visible_holder',
        hiddenholder: '#hidden_holder',
        reparseform: this.closest('form')
    }, options);



    this.change(function () {
        switchFormPart(settings.visibleholder, 
            settings.hiddenholder, 
            ********this.checked, *********** <- I would like this as a parameter
            settings.reparseform
        );
    });
};

Answer 1

You can pass a string like "checked" or "val" as parameter and then:

this.change(function () {
    switchFormPart(settings.visibleholder, 
        settings.hiddenholder, 
        param in this ? this[param] : $(this)[param](),
        settings.reparseform
    );
});

If param is "checked", it will do equivalent to this.checked

If param is "val", it will do equivalent to $(this).val()

And so on.

Look into bracket notation, conditional operator and in operator