[1.9 vote] jQuery.fn.data( callback( index, data ) ) - Fixes #12397

[gnarf]

Sizes - compared to master
    258888      (+167)  dist/jquery.js                
     92841       (+60)  dist/jquery.min.js            
     33218       (+11)  dist/jquery.min.js.gz  

Proposal for a new signature to jQuery.fn.data()

Trac Ticket: http://jqbug.com/12397

[rwaldron]

+1, Nice consistency with the rest of proto method APIs

What about something like...

$( selector ).data(function( k , data ) {
  return {
    a: data.a || "alpha",
    b: "beta"
  };
});

[gnarf]

The return isn't happy, for consistency, the data object itself must be modified instead of assigning a new object. You could just extend tho...

$( selector ).data(function( k , data ) {
  jQuery.extend( data, {
    a: data.a || "alpha",
    b: "beta"
  });
});

I think making the backend of the API do this would just pollute it, would people would also expect missing keys to be deleted?

[gnarf]

Dealing with two conflicting patterns here, the fn.text( function( index, oldText ) { return newText; }) and the fact that fn.data() should NEVER change in the lifetime of that object, only its properties.

It might make sense to pass the return value into elem.data( obj ); ? I think its easier to have it be like each, and just ignore the return value, perhaps have a return false exit?

[gnarf]

@rwldrn - If we wanted to try to be consistent with the other collection setters it might look something like this:

if ( jQuery.isFunction( key ) ) {
    return this.each( function( index ) {
        var result = key( index, jQuery( this ).data() );
        if ( typeof result === "object" ) {
            jQuery( this ).data( result );
        }
    });
}

10 bytes heavier on the gzip size - perhaps useful?

[rwaldron]

Sorry, I was both +1'ing the addition for being consistent and separately asking about API possibilities. I was and still am mobile, so I hadn't actually tested that, just tapped it out ;)

[rkatic]

@gnarf37 Using the returned value to update data seems consistent with other APIs, but the typeof result === "object" check seems wrong. Why not result !== undefined?

[staabm]

Better use $.data() instead, for performance reasons...

[gnarf]

For consistency we can't. It must pass through the chunk of code that can read html attrs.

[gnarf]

@rkatic If a string, boolean, etc is returned, it can't be set to "data" -- only objects can be extended onto the data object.

[rkatic]

@gnarf37 Right... for a moment I supposed it was about jQuery.fn.data( name, callback( index, value ) ). My bad.

Btw. also null can not be extended.

[dmethvin]

Not voted in, see ticket.