Y.ButtonGroup

Problem

I have multiple Y.Button instances that are logically associated and need to be managed as a group.

For example, you may need a radio group, so when one button becomes selected, the others are unselected. Or a checkbox group, which allows you to select multiple buttons and at some point you need to obtain the values of all selected buttons.

Note: A push group is really just a checkbox group, but with Y.Button instances whose types are push as opposed to toggle.

Methods

addButton - Adds a button to the group
getButtons - Returns an array of Y.Button instances assigned to the group
getSelectedButtons - Returns an array of Y.Button instances that are currently selected
getSelectedValues - Returns an array of the values of select buttons (sugar)

Attributes

type ('checkbox' [default], or 'radio')

Events

selectionChange - Fires after the selected state on a grouped button changes.

Dependencies

button-base (requires: base, classnamemanager, node)

Example

// Instantiation
group = new Y.ButtonGroup({type: 'radio'});
buttonA = new Y.Button({srcNode: "#foo"});
buttonB = new Y.Button({srcNode: "#bar"});

// Interaction
group.addButton(ButtonA);
group.addButton(ButtonB);

buttonA.select();
selected = group.getSelectedButtons(); // Returns buttonA

buttonB.select();
selected = group.getSelectedButtons(); // Returns buttonB

Considerations

Add support for a buttons attribute in the Y.ButtonGroup config object to add all buttons on instantiation. Update: see comment #4
Add support for a srcNodes selector attribute in the Y.ButtonGroup config object to create Y.Button instances for each node and add to the group. Update: see comment #4
Add support for a click event (exact name TBD) which fires when any button in the group is clicked. This would be most applicable to push button groups.

Actually, Y.Button creating nodes on the fly was a late addition. It would be preferable for the developer to use Y.Node.create() so then they have full control over the button. But feedback was that it seemed logical for Y.Button to also create buttons, which does make sense, so I added that in. If srcNode is empty at instantiation, it assigns that attritbute as Y.Node.create('<button></button>');.

Instead of Y.Button supporting value directly, it abstracts it out into a label attribute (which I think is what YUI 2 did). But now that I review the code that renders that attribute, I see an issue:

_renderLabel: function (value) {
    var node = this.getNode();
    node.set(node.test('input') ? 'value' : 'text', value);
},

It works fine for <div>, <a>, etc..., and since <input> only has a value attribute (no innerHTML) it will work fine for that as well. But what about a <button> node, which has both value and innerHTML/text? A single label attribute won't work, so I'll have to fix that.

It's not quite as simple as just throwing in a value attribute, because what happens here?

var button = new Y.Button({
    srcNode: Y.Node.create('<div></div>'),
    label: 'I am a Button!',
    value: 'No you are not, you just look like one'
})

<button> and <input> both have a value attribute, but a <div>, <a>, etc... do not. So does Y.Button just ignore the value property? Does it assign it as a custom attribute? It's probably one of those "You should know better that to do this" things, but you never know, and I haven't had a chance to fully think through it yet.

So, I'll work to resolve this issue before 3.5.0pr2.

Good question. Thanks

derek/gist:1597168