calcite-card does not properly handle dynamically added footer slot content

[mjuniper]

Check existing issues

• I have checked for existing issues to avoid duplicates

Actual Behavior

Dynamically added footer slots do not render.

Expected Behavior

Dynamically added footer slots like <div slot="footer-end"> will render.

Reproduction Sample

I think this can only be reproduced by creating a stencil component that uses calcite-card. I could probably do this in React Codesandbox but I don't know react well enough.

Reproduction Steps

Create a component like this:

import { Component, Host, State, VNode, h } from '@stencil/core';

@Component({
  tag: 'parent-component',
  // styleUrl: 'parent-component.css',
  shadow: true,
})
export class ParentComponent {

  // The button works as expected, toggling the slot on and off
  // But _only_ if the initial value of showSlot is true
  @State() showSlot = false;

  maybeRenderSlot(slotName): VNode {
    if (this.showSlot) {
      return <div slot={slotName}>foobar</div>;
    }
  }

  render() {
    return (
      <Host data-element="parent-component">
        This is the parent component
        <calcite-button onClick={_ => this.showSlot = !this.showSlot}>Toggle Slot</calcite-button>
        {/* slotted component is just a very simple stencil component with a named slot
            to try to determine if the problem is specific to calcite-card
            slotted component works as expected
        <slotted-component>
          {this.maybeRenderSlot("main")}
        </slotted-component> */}
        <calcite-card>
          WAT
          {/* <div slot="footer-start">foo</div> */}
          {this.maybeRenderSlot("footer-end")}
        </calcite-card>
      </Host>
    );
  }
}

Then run the samples and observe that the calcite-button in the component works when the initial value of showSlot is true but not when the initial value of showSlot is false.

Reproduction Version

2.11

Relevant Info

I think this can be fixed by doing something like this in calcite-card:

@State() hasFooterStart = false;

@State() hasFooterEnd = false;

get hasFooter(): boolean {
  return this.hasFooterStart || this.hasFooterEnd;
}

private handleFooterStartSlotChange = (event: Event): void => {
  this.hasFooterStart = slotChangeHasAssignedElement(event);
};

private handleFooterEndSlotChange = (event: Event): void => {
  this.hasFooterEnd = slotChangeHasAssignedElement(event);
};

private renderFooter(): VNode {
  const { hasFooter } = this;
  return (
    <footer class={CSS.footer} hidden={!hasFooter}>
      <slot name={SLOTS.footerStart} onSlotchange={this.handleFooterStartSlotChange} />
      <slot name={SLOTS.footerEnd} onSlotchange={this.handleFooterEndSlotChange} />
    </footer>
  );
}

Regression?

No response

Priority impact

impact - p2 - want for an upcoming milestone

Impact

I causes one of the components we commonly use on customer sites to not work properly.

Calcite package

• @esri/calcite-components
• @esri/calcite-components-angular
• @esri/calcite-components-react
• @esri/calcite-design-tokens
• @esri/eslint-plugin-calcite-components

Esri team

ArcGIS Hub

[geospatialem]

Will need to address #6059 to mitigate.

[rweber-esri]

I'm observing the same issue on 2.12.1 even when we immediately slot content into calcite-card's footer-start & footer-end slots. When I inspect the DOM using Chrome Dev Tools, I can see the content is being passed into the slot, but it's not visible to the user. FWIW, we (Hub) are rendering the calcite-card by other Stencil components (JSX) we internally develop/maintain that are lazy loaded, which could be related (maybe a render race condition related to the async loading that results in similar observations as if we had dynamically rendered the content into the slot?). What's strange is that other slots in this component that also use the getSlotted pattern (e.g. slot="title") seem to work in my use case.

Adding a JSX key to the elements with the slot="footer-start|footer-end" attributes doesn't seem to help.

This might be something worth prioritizing sooner rather than later, if possible.