From 9fc610df63e1d8c78cde1affda2ecc942573e8cd Mon Sep 17 00:00:00 2001
From: JC Franco <jfranco@esri.com>
Date: Mon, 13 May 2024 11:37:58 -0700
Subject: [PATCH] feat(segmented-control-item): allow displaying and icon when
 items are empty with a start/end icon (#9300)

*Related Issue:** #6413

## Summary

This updates `segmented-control-item` to display a centered icon when
specified and the item is empty.

**Note:** this removes using `value` as a fallback label as non-breaking
for the following reasons:

* this behavior is
[intentional](https://github.com/Esri/calcite-design-system/blob/main/packages/calcite-components/src/components/segmented-control-item/segmented-control-item.e2e.ts#L38-L46),
but there is no explicit spec for it in the [original
issue](https://github.com/Esri/calcite-design-system/issues/5),
[PR](https://github.com/Esri/calcite-design-system/pull/72) nor
[documentation](https://developers.arcgis.com/calcite-design-system/components/segmented-control/)
* it is inconsistent with how other components expect text to be
provided
* it [breaks if there's any
whitespace](https://codepen.io/jcfranco/pen/XWwWGEy?editors=1000)
* the current behavior will lead to label that might not be
user-friendly in most cases (e.g., casing, localization)
---
 .../segmented-control-item/resources.ts       | 10 ++-
 .../segmented-control-item.e2e.ts             | 15 +---
 .../segmented-control-item.scss               | 38 +++++----
 .../segmented-control-item.tsx                | 77 ++++++++++++-------
 .../segmented-control.stories.ts              | 26 +++++++
 5 files changed, 109 insertions(+), 57 deletions(-)

diff --git a/packages/calcite-components/src/components/segmented-control-item/resources.ts b/packages/calcite-components/src/components/segmented-control-item/resources.ts
index 7c4dfb8a978..ee5ef83894b 100644
--- a/packages/calcite-components/src/components/segmented-control-item/resources.ts
+++ b/packages/calcite-components/src/components/segmented-control-item/resources.ts
@@ -1,7 +1,15 @@
+import { Scale } from "../interfaces";
+
 export const SLOTS = {
   input: "input",
 };
 
 export const CSS = {
-  segmentedControlItemIcon: "segmented-control-item-icon",
+  label: "label",
+  labelScale: (scale: Scale) => `label--scale-${scale}` as const,
+  labelHorizontal: "label--horizontal",
+  labelOutline: "label--outline",
+  labelOutlineFill: "label--outline-fill",
+  icon: "icon",
+  iconSolo: "icon--solo",
 };
diff --git a/packages/calcite-components/src/components/segmented-control-item/segmented-control-item.e2e.ts b/packages/calcite-components/src/components/segmented-control-item/segmented-control-item.e2e.ts
index a280103baff..704e861001c 100644
--- a/packages/calcite-components/src/components/segmented-control-item/segmented-control-item.e2e.ts
+++ b/packages/calcite-components/src/components/segmented-control-item/segmented-control-item.e2e.ts
@@ -1,5 +1,6 @@
 import { newE2EPage } from "@stencil/core/testing";
 import { renders, hidden } from "../../tests/commonTests";
+import { CSS } from "./resources";
 
 describe("calcite-segmented-control-item", () => {
   describe("renders", () => {
@@ -35,21 +36,11 @@ describe("calcite-segmented-control-item", () => {
     expect(value).toBe("test-value");
   });
 
-  it("uses value as fallback label", async () => {
-    const page = await newE2EPage();
-    await page.setContent(
-      "<calcite-segmented-control-item value='test-value' checked></calcite-segmented-control-item>",
-    );
-
-    const label = await page.find("calcite-segmented-control-item >>> label");
-    expect(label).toEqualText("test-value");
-  });
-
   it("renders icon at start if requested", async () => {
     const page = await newE2EPage();
     await page.setContent(`
     <calcite-segmented-control-item icon-start="car">Content</calcite-accordion-item>`);
-    const icon = await page.find("calcite-segmented-control-item >>> .segmented-control-item-icon");
+    const icon = await page.find(`calcite-segmented-control-item >>> .${CSS.icon}`);
     expect(icon).not.toBe(null);
   });
 
@@ -57,7 +48,7 @@ describe("calcite-segmented-control-item", () => {
     const page = await newE2EPage();
     await page.setContent(`
     <calcite-segmented-control-item>Content</calcite-accordion-item>`);
-    const icon = await page.find("calcite-segmented-control-item >>> .segmented-control-item-icon");
+    const icon = await page.find(`calcite-segmented-control-item >>> .${CSS.icon}`);
     expect(icon).toBe(null);
   });
 
diff --git a/packages/calcite-components/src/components/segmented-control-item/segmented-control-item.scss b/packages/calcite-components/src/components/segmented-control-item/segmented-control-item.scss
index f96fca806be..3f666f4130d 100644
--- a/packages/calcite-components/src/components/segmented-control-item/segmented-control-item.scss
+++ b/packages/calcite-components/src/components/segmented-control-item/segmented-control-item.scss
@@ -84,40 +84,48 @@
   :host([checked]) .label--outline-fill {
     @apply outline-none;
   }
-  :host([checked]) label:not([class~="label--outline"]) .segmented-control-item-icon {
+  :host([checked]) label:not([class~="label--outline"]) .icon {
     color: highlightText;
   }
 }
 
-// icon
-.segmented-control-item-icon {
+.icon {
   @apply relative
     m-0
     inline-flex;
   line-height: inherit;
+
+  margin-inline-start: var(--calcite-internal-segmented-control-icon-margin-start);
+  margin-inline-end: var(--calcite-internal-segmented-control-icon-margin-end);
+}
+
+:host([icon-start]) .label--scale-s {
+  --calcite-internal-segmented-control-icon-margin-end: theme("margin.2");
 }
 
-:host([icon-start]) .label--scale-s .segmented-control-item-icon {
-  margin-inline-end: theme("margin.2");
+:host([icon-end]) .label--scale-s {
+  --calcite-internal-segmented-control-icon-margin-start: theme("margin.2");
 }
 
-:host([icon-end]) .label--scale-s .segmented-control-item-icon {
-  margin-inline-start: theme("margin.2");
+:host([icon-start]) .label--scale-m {
+  --calcite-internal-segmented-control-icon-margin-end: theme("margin.3");
 }
 
-:host([icon-start]) .label--scale-m .segmented-control-item-icon {
-  margin-inline-end: theme("margin.3");
+:host([icon-end]) .label--scale-m {
+  --calcite-internal-segmented-control-icon-margin-start: theme("margin.3");
 }
 
-:host([icon-end]) .label--scale-m .segmented-control-item-icon {
-  margin-inline-start: theme("margin.3");
+:host([icon-start]) .label--scale-l {
+  --calcite-internal-segmented-control-icon-margin-end: theme("margin.4");
 }
 
-:host([icon-start]) .label--scale-l .segmented-control-item-icon {
-  margin-inline-end: theme("margin.4");
+:host([icon-end]) .label--scale-l {
+  --calcite-internal-segmented-control-icon-margin-start: theme("margin.4");
 }
-:host([icon-end]) .label--scale-l .segmented-control-item-icon {
-  margin-inline-start: theme("margin.4");
+
+.label .icon--solo {
+  --calcite-internal-segmented-control-icon-margin-start: 0;
+  --calcite-internal-segmented-control-icon-margin-end: 0;
 }
 
 @include base-component();
diff --git a/packages/calcite-components/src/components/segmented-control-item/segmented-control-item.tsx b/packages/calcite-components/src/components/segmented-control-item/segmented-control-item.tsx
index f03bf8183a2..91281352cd8 100644
--- a/packages/calcite-components/src/components/segmented-control-item/segmented-control-item.tsx
+++ b/packages/calcite-components/src/components/segmented-control-item/segmented-control-item.tsx
@@ -6,10 +6,11 @@ import {
   h,
   Host,
   Prop,
+  State,
   VNode,
   Watch,
 } from "@stencil/core";
-import { toAriaBoolean } from "../../utils/dom";
+import { slotChangeHasContent, toAriaBoolean } from "../../utils/dom";
 import { Appearance, Layout, Scale } from "../interfaces";
 import { CSS, SLOTS } from "./resources";
 
@@ -47,8 +48,7 @@ export class SegmentedControlItem {
    * The component's value.
    */
   // eslint-disable-next-line @stencil-community/strict-mutable -- updated by form module
-  @Prop({ mutable: true })
-  value: any | null;
+  @Prop({ mutable: true }) value: any | null;
 
   /**
    * Specifies the appearance style of the component inherited from parent `calcite-segmented-control`, defaults to `solid`.
@@ -77,50 +77,67 @@ export class SegmentedControlItem {
   //
   //--------------------------------------------------------------------------
 
-  render(): VNode {
-    const { appearance, checked, layout, scale, value } = this;
-
-    const iconStartEl = this.iconStart ? (
+  private renderIcon(icon: string, solo: boolean = false): VNode {
+    return icon ? (
       <calcite-icon
-        class={CSS.segmentedControlItemIcon}
+        class={{
+          [CSS.icon]: true,
+          [CSS.iconSolo]: solo,
+        }}
         flipRtl={this.iconFlipRtl}
-        icon={this.iconStart}
-        key="icon-start"
+        icon={icon}
         scale="s"
       />
     ) : null;
+  }
 
-    const iconEndEl = this.iconEnd ? (
-      <calcite-icon
-        class={CSS.segmentedControlItemIcon}
-        flipRtl={this.iconFlipRtl}
-        icon={this.iconEnd}
-        key="icon-end"
-        scale="s"
-      />
-    ) : null;
+  render(): VNode {
+    const { appearance, checked, layout, scale, value } = this;
 
     return (
       <Host aria-checked={toAriaBoolean(checked)} aria-label={value} role="radio">
         <label
           class={{
-            "label--scale-s": scale === "s",
-            "label--scale-m": scale === "m",
-            "label--scale-l": scale === "l",
-            "label--horizontal": layout === "horizontal",
-            "label--outline": appearance === "outline",
-            "label--outline-fill": appearance === "outline-fill",
+            [CSS.label]: true,
+            [CSS.labelScale(scale)]: true,
+            [CSS.labelHorizontal]: layout === "horizontal",
+            [CSS.labelOutline]: appearance === "outline",
+            [CSS.labelOutlineFill]: appearance === "outline-fill",
           }}
         >
-          {this.iconStart ? iconStartEl : null}
-          <slot>{value}</slot>
-          <slot name={SLOTS.input} />
-          {this.iconEnd ? iconEndEl : null}
+          {this.renderContent()}
         </label>
       </Host>
     );
   }
 
+  private renderContent(): VNode | VNode[] {
+    const { hasSlottedContent, iconEnd, iconStart } = this;
+    const effectiveIcon = iconStart || iconEnd;
+    const canRenderIconOnly = !hasSlottedContent && effectiveIcon;
+
+    if (canRenderIconOnly) {
+      return [this.renderIcon(effectiveIcon, true), <slot onSlotchange={this.handleSlotChange} />];
+    }
+
+    return [
+      this.renderIcon(iconStart),
+      <slot onSlotchange={this.handleSlotChange} />,
+      <slot name={SLOTS.input} />,
+      this.renderIcon(iconEnd),
+    ];
+  }
+
+  //--------------------------------------------------------------------------
+  //
+  //  Private Methods
+  //
+  //--------------------------------------------------------------------------
+
+  private handleSlotChange = (event: Event): void => {
+    this.hasSlottedContent = slotChangeHasContent(event);
+  };
+
   //--------------------------------------------------------------------------
   //
   //  Private Properties
@@ -129,6 +146,8 @@ export class SegmentedControlItem {
 
   @Element() el: HTMLCalciteSegmentedControlItemElement;
 
+  @State() hasSlottedContent = false;
+
   //--------------------------------------------------------------------------
   //
   //  Events
diff --git a/packages/calcite-components/src/components/segmented-control/segmented-control.stories.ts b/packages/calcite-components/src/components/segmented-control/segmented-control.stories.ts
index 1a6ab0a60e0..5b8cf7cff93 100644
--- a/packages/calcite-components/src/components/segmented-control/segmented-control.stories.ts
+++ b/packages/calcite-components/src/components/segmented-control/segmented-control.stories.ts
@@ -137,3 +137,29 @@ export const validationMessage_TestOnly = (): string => html`
     </calcite-segmented-control>
   </div>
 `;
+
+export const iconOnly = (): string => html`
+  <h1>small</h1>
+  <calcite-segmented-control scale="s">
+    <calcite-segmented-control-item icon-start="banana" value="react" checked></calcite-segmented-control-item>
+    <calcite-segmented-control-item icon-start="gear" value="ember"></calcite-segmented-control-item>
+    <calcite-segmented-control-item icon-start="3d-glasses" value="angular"></calcite-segmented-control-item>
+    <calcite-segmented-control-item icon-start="effects" value="vue"></calcite-segmented-control-item>
+  </calcite-segmented-control>
+
+  <h1>medium</h1>
+  <calcite-segmented-control scale="m">
+    <calcite-segmented-control-item icon-end="banana" value="react" checked></calcite-segmented-control-item>
+    <calcite-segmented-control-item icon-end="gear" value="ember"></calcite-segmented-control-item>
+    <calcite-segmented-control-item icon-end="3d-glasses" value="angular"></calcite-segmented-control-item>
+    <calcite-segmented-control-item icon-end="effects" value="vue"></calcite-segmented-control-item>
+  </calcite-segmented-control>
+
+  <h1>medium</h1>
+  <calcite-segmented-control scale="l">
+    <calcite-segmented-control-item icon-end="banana" value="react" checked></calcite-segmented-control-item>
+    <calcite-segmented-control-item icon-end="gear" value="ember"></calcite-segmented-control-item>
+    <calcite-segmented-control-item icon-end="3d-glasses" value="angular"></calcite-segmented-control-item>
+    <calcite-segmented-control-item icon-end="effects" value="vue"></calcite-segmented-control-item>
+  </calcite-segmented-control>
+`;