I would love have some low level populate functionality. Was running into that again today (specifically populating Controllers that expose .val() method) and with Model + Observe it would be really easy to tie forms and models both ways. I am not sure if it takes care of nested params at the moment though. Wouldn't it return

params['test[key]']

instead of

params.test.key

?

var name = $(this).attr("name"), parts = name.match(keyBreaker),
    value = params;
for(var i = 0; i < parts.length; i++) {
    if(value[parts[i]]) {
        value = value[parts[i]];
    } else {
        return '';
    }
}

Good call! Names using bracket notation, e.g. foo[] aren't handled. I'll add that to my next commit on this.

Sweet. I can add some tests if you want.

This function has it's if ( value ) condition and it can lead to errors. For example if you want to switch current edited item and it's field is empty then if(value) is false and last edited value stays.
This condition isn't necessary .

@selecton Good catch. I assume if ( value !== undefined) would be the proper test. I'll make the changes now.