Time varying textnode

[ewen]

Hello,

I am trying to create "time varying" textnodes using flapjax. I am able to create time-varying dom element using functions such as SPAN, P, DIV and so on, but the TEXT function does not seem to work with behaviours.
Did I miss a function to build such nodes?

I ended with a custom implementation but I wonder if it is the right way to do this:

var TEXT2 = function (textB){
        var elt = document.createTextNode();
        elt.nodeValue=textB.valueNow();

        textB.liftB(function(currentVal) {
                            elt.nodeValue = currentVal;
            });

        return elt;
    }

Thank you !

Ewen.

[Arjun Guha]

Hi Ewen,

Your function should work just fine. Or, use the Flapjax function TEXTB.

 We ought to rename that to just TEXT. That "B" suffix indicates that it consumes behaviors. It is a holdover from the first version of Flapjax, where all functions were suffixed B or E. 

Arjun

[ewen]

Hi Arjun,

Yes I noticed the TEXTB function but it returns a Behaviour and not a DOM element and thus can't be directly used by external DOM manipulation libraries.
I will keep using my implementation since it seems to work fine.

Thank you very much for your help :)

Ewen.

[Arjun Guha]

There is no good reason for TEXTB to return a behavior, is there? I think Flapjax should just return a constant text node like yours.

Arjun

Ewen.

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[Leo Meyerovich]

Hi all,

The issue motivating a behavioral result rather than a raw DOM node for the DOM construction methods is that style changes may require reconstruction of the DOM node. 

Most style updates were handled destructively inlace (e.g., {color: myColorB}). However, if the style object was a behavior ( styleB ) and the set of properties changed, the object would be reconstructed to ensure correct handling of attributes that are no longer specified (e.g., styleB = {fontSize: 2} says nothing about color). A smarter version might be inplace by diffing the two objects and somehow inferring the default value, but that seems hard.

- Leo

[Arjun Guha]

Ah, I see! Yes, time-varying styles are quite complex.