Button Icons/FontAwesome regression no longer supports fa-spin

[rskabelund]

since this was added:
https://github.com/jupyter-widgets/ipywidgets/blob/master/ipywidgets/widgets/widget_button.py#L65-L73

we are no longer able to pass in additional fa classes to specify fa-spin or fa-lg etc.

I really liked my spinning gear icon button before this change...

i.e.

from ipywidgets import Button
Button(description='Running...', icon='fa-gear fa-spin fa-lg')

it will error on the add of the DOMTokenList due to the spaces in the string
https://github.com/jupyter-widgets/ipywidgets/blob/master/packages/controls/src/widget_button.ts#L91

[rskabelund]

Running on ipywidgets 5.2.2

[rskabelund]

@jasongrout what would be the path forward to allow multiple font awesome parameters? Are there existing accommodations for this that I am missing?

[kebwi]

I was just wishing yesterday for multiple icons on a button and found this discussion. The implication is that it used to work and such behavior was explicitly removed? Why not leave it in and let the user decide if they find multiple icons useful? I could use it frankly.

Thanks.

[rskabelund]

@kebwi I ended up creating a custom widget for my purposes using the ipywidgets cookiecutter template. But, yeah, disappointed this support is no longer available with little explanation why.

[rskabelund]

Here is an example custom font awesome button:

Python Model:

from traitlets import Unicode, Bool, validate, TraitError, Any
from ipywidgets import DOMWidget, register

@register
class FaButton(DOMWidget):
    _view_name = Unicode('FaButtonView').tag(sync=True)
    _view_module = Unicode('fabutton_widget').tag(sync=True)
    _view_module_version = Unicode('0.1.0').tag(sync=True)

    # Attributes
    description = Unicode('ww', help="Button Text").tag(sync=True)
    icon = Unicode('fa-cloud-download', help="Font Awesome String").tag(sync=True)
    disabled = Bool(False, help="Enable or disable button").tag(sync=True)
    callback_event = Any().tag(sync=True)

Javascript View:

%%javascript
require.undef('fabutton_widget');

define('fabutton_widget', ["@jupyter-widgets/base"], function(widgets) {

    var FaButtonView = widgets.DOMWidgetView.extend({

        // Render the view.
        render: function() {
            this.btn = document.createElement('button');            
            this.btn.setAttribute("class", "jupyter-button widget-button");
            
            this.update_text();
            
            this.el.appendChild(this.btn);
            
            this.el.setAttribute("class", "widget-html-content");
            
            // Python -> JavaScript update
            this.model.on('change:icon', this.update_text, this);
            this.model.on('change:description', this.update_text, this);

        },

        events: {
            // List of events and their handlers.
            'click': 'handle_click'
        },   
        
        handle_click: function() {
            if (event.target.tagName == 'BUTTON') {
                this.model.set('callback_event', {'target':event.target.innerHTML, 'data':event.target.dataset, 'type': 'button_click' , 'name':event.originalEvent , 'timeStamp':event['timeStamp']}); 
                this.touch();
            }
        },

        update_text: function() {
            this.btn.innerHTML = '<i class="fa ' + this.model.get('icon') + '" aria-hidden="true"></i>' + this.model.get('description');
        },

    });

    return {
        FaButtonView: FaButtonView
    };
});

Usage:

def handle_btn_click_callback(e):
    print('hello from custom btn widget')
    
    
btn = FaButton(icon='fa-spin fa-gear', description = 'Hello')
btn.observe(handle_btn_click_callback, 'callback_event')
display(btn)

[kebwi]

Hmmm. Thanks. I admit, I've haven't delved into custom widgets yet. I guess it's time to roll up my sleeves.

[vidartf]

I did a bit of digging in the code, and I think this is where this behavior was changed: #427 (after this it was no longer possible to define multiple icon classes). That is three years ago, although the deprecation warning was added a few months later. The purpose of that was to reduce/remove our dependency on jQuery.

It might be possible to get accepted a PR that re-adds support for multiple classes. Change this:

ipywidgets/packages/controls/src/widget_button.ts

Line 91 in a311d75

i.classList.add('fa-' + icon);

To this:

i.className += 'fa-' + icon;

You would then be able to use (the slightly hackish):

from ipywidgets import Button
Button(description='Running...', icon='gear fa-spin fa-lg')

[jasongrout]

Perhaps something like:

icon.split(/[\s]+/).filter(Boolean).map(v => `fa-${v}`).join(' ')

would let the icon take multiple values.

[vidartf]

Note: The change above only outlines how to support multiple icon classes. The other change that was done was to automatically prefix with fa-. That seems to have been done (by mistake?) in #555 . Since this has been in for such a long time now, I don't think that can be considered a non-breaking fix anymore.

[jasongrout]

This may be a simpler way to prepend the fa- to each word:

icon.replace(/\b(\w)/g, 'fa-$1')

[jasongrout]

The other change that was done was to automatically prefix with fa-. That seems to have been done (by mistake?) in #555 . Since this has been in for such a long time now, I don't think that can be considered a non-breaking fix anymore.

That was introduced in 6.0, apparently (at least #555 was in 6.0).

[jasongrout]

I think it would be great if someone put in a PR adding back in support for multiple icons, probably by just changing the one line that Vidar points out above (I give several different ways to prepend fa- to each thing in the list above).

Setting as a good first issue.

[vidartf]

That was introduced in 6.0

Yes, which is why I think we simply said "this is the new behavior now" instead of saying "this is a bug, lets fix it". 🤷‍♂