RFC: Radio Groups as card layouts

[marcjulian]

Which scope/s are relevant/related to the feature request?

radio-group

Information

Allow Radio Groups to be styled in any layout such as these cards.

label is part of BrnRadioComponent how to style the label for custom layouts? Should the label be extracted from BrnRadioComponent to be styled by the user and follow a similar API as shadcn?

Shadcn API

<RadioGroup defaultValue="option-one">
 <div>
            <RadioGroupItem
              value="card"
              id="card"
              className="peer sr-only"
              aria-label="Card"
            />
            <Label
              htmlFor="card"
              className="flex flex-col items-center justify-between rounded-md border-2 border-muted bg-transparent p-4 hover:bg-accent hover:text-accent-foreground peer-data-[state=checked]:border-primary [&:has([data-state=checked])]:border-primary"
            >
              <svg
                xmlns="http://www.w3.org/2000/svg"
                viewBox="0 0 24 24"
                fill="none"
                stroke="currentColor"
                strokeLinecap="round"
                strokeLinejoin="round"
                strokeWidth="2"
                className="mb-3 h-6 w-6"
              >
                <rect width="20" height="14" x="2" y="5" rx="2" />
                <path d="M2 10h20" />
              </svg>
              Card
            </Label>
          </div>
   ...
</RadioGroup>

Describe any alternatives/workarounds you're currently using

No response

I would be willing to submit a PR to fix this issue

• Yes
• No

[goetzrobin]

How about we make styles and classes for the label, indicator, input inside the brn-radio inputs that can be overwritten?
That way we have more flexibility on how to style the actual button. The anatomy of the brn-radio is inspired by Material, and I think in the case you are describing the label would be marked with sr-only and the indicator/touchTarget is where you would style the Card

[marcjulian]

Input component design

API design when we would add class inputs for label, indicator and input for brn-radio could look like

<brn-radio-group hlm class="grid grid-cols-3 gap-4" [(ngModel)]="card">
  <brn-radio hlm value="card" labelClass="...">
    <svg>...</svg>
    Card
  </brn-radio>
   ...
</brn-radio-group>

What about refactoring the hlm directives to components to use them instead

<hlm-radio-group class="grid grid-cols-3 gap-4" [(ngModel)]="card">
  <hlm-radio value="card" labelClass="...">
    <svg>...</svg>
    Card
  </hlm-radio>
   ...
</hlm-radio-group>

Extract label component design

What if we extract the label from brn-radio:

// brn-radio.component.ts
<div style="display: flex; height: fit-content; width: fit-content" (click)="_onTouchTargetClick($event)">
  <ng-content select="[target],[indicator]" />
</div>
<input 
  #input 
  style="position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border-width: 0;"
  type="radio" 
  [id]="inputId" 
  [checked]="checked" 
  [disabled]="disabled" 
  [attr.name]="name" 
  [attr.value]="value" 
  [required]="required" 
  [attr.aria-label]="ariaLabel" 
  [attr.aria-labelledby]="ariaLabelledby" 
  [attr.aria-describedby]="ariaDescribedby" 
  (change)="_onInputInteraction($event)" 
  (click)="_onInputClick($event)" 
/>
- <label style="display: flex; height: fit-content; width: fit-content" [for]="inputId">
  <ng-content></ng-content>
- </label>

The API could look like as follow when we pull out the label from brn-radio, but we also need to handle <label [for]="inputId > each time.

<brn-radio-group hlm class="grid grid-cols-3 gap-4" [(ngModel)]="version">
  <brn-radio hlm value="card">
    <label class="...">
      <svg>...</svg>
      Card
    </label>
  </brn-radio>
  ...
</brn-radio-group>

Or with hlm components

<hlm-radio-group class="grid grid-cols-3 gap-4" [(ngModel)]="version">
  <hlm-radio value="card">
    <label class="...">
      <svg>...</svg>
      Card
    </label>
  </hlm-radio>
  ...
</hlm-radio-group>

[marcjulian]

You think it would be better to move the card layout into the indicator selector, something like this:

<brn-radio-group hlm class="grid grid-cols-3 gap-4" [(ngModel)]="card">
  <brn-radio hlm value="card" labelClass="sr-only">
    <!-- projected into indicator: touch area -->
    <div indicator class="...">
      <svg>...</svg>
      Card
    </div>
    <!-- projected into label: apply sr-only class-->
    Card
  </brn-radio>
</brn-radio-group>

[goetzrobin]

Interesting. What are you thinking?

[goetzrobin]

After reviewing this I think my absolute favorite would be this. And inside hlm-radio we allow you access to the label classes and styles.

<hlm-radio-group class="grid grid-cols-3 gap-4" [(ngModel)]="version">
  <hlm-radio value="card">
      Card
  </hlm-radio>
  ...
</hlm-radio-group>

And then for a custom radio we could do something like this:

<brn-radio-group class="grid grid-cols-3 gap-4" [(ngModel)]="card">
  <brn-radio value="card" labelClass="sr-only">
    <!-- projected into indicator: touch area -->
    <div indicator class="...">
      <svg>...</svg>
      Card
    </div>
    <!-- projected into label: apply sr-only class-->
    Card
  </brn-radio>
</brn-radio-group>

[marcjulian]

This sounds good to me.

<hlm-radio-group class="grid grid-cols-3 gap-4" [(ngModel)]="version">
  <hlm-radio value="card">
      Card
  </hlm-radio>
  ...
</hlm-radio-group>

But the for the custom radio, I don't like that we need to repeat the label. What is there reason not to project the custom radio into the label and apply the needed styles?

[goetzrobin]

@marcjulian just getting back to this. Were you able to get this to work? Anything I can do to help

[marcjulian]

@goetzrobin I started with converting the hlm radiogroup directives to components. However, it is not working yet.

For example the hlm-radio wraps brn-radio, but brn-radio injects the BrnRadioGroupComponent which is undefined. Should I create a draft PR and we can discuss a solution there? Is it possible for HlmRadio to extend BrnRadio?

@Component({
	selector: 'hlm-radio',
	template: `
		<brn-radio [class]="_computedClass()" [value]="value()" [disabled]="disabled()">
			<ng-content></ng-content>
		</brn-radio>
	`,
	imports: [BrnRadioComponent],
	standalone: true,
	host: {
		class: 'block',
	},
})
export class HlmRadioComponent {

[goetzrobin]

@marcjulian that works for me. I was also going to take a crack at it, but if you already started we can combine efforts!