From 43f06f2be304b5b20809e64039adc1b389533454 Mon Sep 17 00:00:00 2001
From: Eric Liu <ericyl.us@gmail.com>
Date: Sun, 29 Nov 2020 15:00:22 -0800
Subject: [PATCH] feat(tabs): proof of concept for keyed tabs

---
 COMPONENT_INDEX.md                       |  41 +++++-
 docs/src/COMPONENT_API.json              | 100 ++++++++++++-
 docs/src/pages/framed/Tabs/TabsV2.svelte |  86 +++++++++++
 src/Tabs/TabsV2.svelte                   | 178 +++++++++++++++++++++++
 src/Tabs/index.js                        |   1 +
 src/index.js                             |   2 +-
 types/Tabs/TabsV2.d.ts                   |  60 ++++++++
 types/index.d.ts                         |   1 +
 8 files changed, 466 insertions(+), 3 deletions(-)
 create mode 100644 docs/src/pages/framed/Tabs/TabsV2.svelte
 create mode 100644 src/Tabs/TabsV2.svelte
 create mode 100644 types/Tabs/TabsV2.d.ts

diff --git a/COMPONENT_INDEX.md b/COMPONENT_INDEX.md
index addbd6e2..088058dc 100644
--- a/COMPONENT_INDEX.md
+++ b/COMPONENT_INDEX.md
@@ -1,6 +1,6 @@
 # Component Index
 
-> 155 components exported from carbon-components-svelte@0.25.1.
+> 156 components exported from carbon-components-svelte@0.25.1.
 
 ## Components
 
@@ -134,6 +134,7 @@
 - [`TableRow`](#tablerow)
 - [`Tabs`](#tabs)
 - [`TabsSkeleton`](#tabsskeleton)
+- [`TabsV2`](#tabsv2)
 - [`Tag`](#tag)
 - [`TagSkeleton`](#tagskeleton)
 - [`TextArea`](#textarea)
@@ -3582,6 +3583,44 @@ None.
 | mouseenter | forwarded | --     |
 | mouseleave | forwarded | --     |
 
+## `TabsV2`
+
+### Types
+
+```ts
+export type TabsV2ItemId = number | string;
+
+export interface TabsV2Item {
+  id: TabsV2ItemId;
+  label?: string;
+  disabled?: boolean;
+}
+```
+
+### Props
+
+| Prop name       | Kind             | Reactive | Type                                      | Default value                    | Description                                 |
+| :-------------- | :--------------- | :------- | :---------------------------------------- | -------------------------------- | ------------------------------------------- |
+| selectedId      | <code>let</code> | Yes      | <code>TabsV2ItemId</code>                 | --                               | Specify the selected tab id                 |
+| selectedIndex   | <code>let</code> | Yes      | <code>number</code>                       | <code>0</code>                   | Specify the selected tab index              |
+| items           | <code>let</code> | No       | <code>TabsV2Item[]</code>                 | <code>[]</code>                  | Provide the tab items                       |
+| type            | <code>let</code> | No       | <code>"default" &#124; "container"</code> | <code>"default"</code>           | Specify the type of tabs                    |
+| iconDescription | <code>let</code> | No       | <code>string</code>                       | <code>"Show menu options"</code> | Specify the ARIA label for the chevron icon |
+| triggerHref     | <code>let</code> | No       | <code>string</code>                       | <code>"#"</code>                 | Specify the tab trigger href attribute      |
+
+### Slots
+
+| Slot name | Default | Props                                                                | Fallback                  |
+| :-------- | :------ | :------------------------------------------------------------------- | :------------------------ |
+| --        | Yes     | <code>{ id: TabsV2ItemId; index: number; item: TabsV2Item; } </code> | --                        |
+| tab       | No      | --                                                                   | <code>{item.label}</code> |
+
+### Events
+
+| Event name | Type       | Detail                                                                                    |
+| :--------- | :--------- | :---------------------------------------------------------------------------------------- |
+| change     | dispatched | <code>{ selectedIndex: number; selectedId: TabsV2ItemId; currentItem: TabsV2Item }</code> |
+
 ## `Tag`
 
 ### Props
diff --git a/docs/src/COMPONENT_API.json b/docs/src/COMPONENT_API.json
index 799b29d9..ac9d6dc9 100644
--- a/docs/src/COMPONENT_API.json
+++ b/docs/src/COMPONENT_API.json
@@ -1,5 +1,5 @@
 {
-  "total": 155,
+  "total": 156,
   "components": [
     {
       "moduleName": "SkeletonText",
@@ -7637,6 +7637,104 @@
       "typedefs": [],
       "rest_props": { "type": "Element", "name": "div" }
     },
+    {
+      "moduleName": "TabsV2",
+      "filePath": "/src/Tabs/TabsV2.svelte",
+      "props": [
+        {
+          "name": "items",
+          "kind": "let",
+          "description": "Provide the tab items",
+          "type": "TabsV2Item[]",
+          "value": "[]",
+          "isFunction": false,
+          "constant": false,
+          "reactive": false
+        },
+        {
+          "name": "selectedIndex",
+          "kind": "let",
+          "description": "Specify the selected tab index",
+          "type": "number",
+          "value": "0",
+          "isFunction": false,
+          "constant": false,
+          "reactive": true
+        },
+        {
+          "name": "selectedId",
+          "kind": "let",
+          "description": "Specify the selected tab id",
+          "type": "TabsV2ItemId",
+          "isFunction": false,
+          "constant": false,
+          "reactive": true
+        },
+        {
+          "name": "type",
+          "kind": "let",
+          "description": "Specify the type of tabs",
+          "type": "\"default\" | \"container\"",
+          "value": "\"default\"",
+          "isFunction": false,
+          "constant": false,
+          "reactive": false
+        },
+        {
+          "name": "iconDescription",
+          "kind": "let",
+          "description": "Specify the ARIA label for the chevron icon",
+          "type": "string",
+          "value": "\"Show menu options\"",
+          "isFunction": false,
+          "constant": false,
+          "reactive": false
+        },
+        {
+          "name": "triggerHref",
+          "kind": "let",
+          "description": "Specify the tab trigger href attribute",
+          "type": "string",
+          "value": "\"#\"",
+          "isFunction": false,
+          "constant": false,
+          "reactive": false
+        }
+      ],
+      "slots": [
+        {
+          "name": "__default__",
+          "default": true,
+          "slot_props": "{ id: TabsV2ItemId; index: number; item: TabsV2Item; }"
+        },
+        {
+          "name": "tab",
+          "default": false,
+          "fallback": "{item.label}",
+          "slot_props": "{}"
+        }
+      ],
+      "events": [
+        {
+          "type": "dispatched",
+          "name": "change",
+          "detail": "{ selectedIndex: number; selectedId: TabsV2ItemId; currentItem: TabsV2Item }"
+        }
+      ],
+      "typedefs": [
+        {
+          "type": "number | string",
+          "name": "TabsV2ItemId",
+          "ts": "type TabsV2ItemId = number | string"
+        },
+        {
+          "type": "{ id: TabsV2ItemId; label?: string; disabled?: boolean; }",
+          "name": "TabsV2Item",
+          "ts": "interface TabsV2Item { id: TabsV2ItemId; label?: string; disabled?: boolean; }"
+        }
+      ],
+      "rest_props": { "type": "Element", "name": "div" }
+    },
     {
       "moduleName": "TagSkeleton",
       "filePath": "/src/Tag/TagSkeleton.svelte",
diff --git a/docs/src/pages/framed/Tabs/TabsV2.svelte b/docs/src/pages/framed/Tabs/TabsV2.svelte
new file mode 100644
index 00000000..9e0ced98
--- /dev/null
+++ b/docs/src/pages/framed/Tabs/TabsV2.svelte
@@ -0,0 +1,86 @@
+<script>
+  import { TabsV2, Button } from "carbon-components-svelte";
+  import Add16 from "carbon-icons-svelte/lib/Add16";
+  import { tick } from "svelte";
+
+  const initialItems = [
+    { id: "id" + 0, label: "Tab 1" },
+    { id: "id" + 1, label: "Tab 2", disabled: true },
+    { id: "id" + 3, label: "Tab 3" },
+  ];
+
+  const differentItems = [
+    { id: "id" + -1, label: "Diff Tab 0" },
+    { id: "id" + 0, label: "Diff Tab 1" },
+    { id: "id" + 1, label: "Diff Tab 2" },
+    { id: "id" + 3, label: "Diff Tab 3" },
+    { id: "id" + 4, label: "Diff Tab 4" },
+  ];
+
+  let selectedIndex;
+  let selectedId;
+  let items = initialItems;
+</script>
+
+<div><strong>selectedIndex:</strong> {selectedIndex}</div>
+
+<div><strong>selectedId:</strong> {selectedId}</div>
+
+<Button
+  on:click="{async () => {
+    items = differentItems;
+    tick().then(() => {
+      selectedId = 'id4';
+    });
+  }}"
+>
+  Update items
+</Button>
+
+<Button
+  on:click="{() => {
+    items = initialItems;
+  }}"
+>
+  Reset
+</Button>
+
+<Button
+  on:click="{() => {
+    selectedIndex = 1;
+  }}"
+>
+  Update selectedIndex
+</Button>
+
+<Button
+  on:click="{() => {
+    selectedId = 'id3';
+  }}"
+>
+  Update selectedId
+</Button>
+
+<TabsV2
+  bind:selectedId
+  bind:selectedIndex
+  items="{items}"
+  let:item
+  let:id
+  let:index
+  on:change="{(e) => {
+    console.log('change', e.detail);
+  }}"
+>
+  <span slot="tab" style="{!item.disabled && 'color: blue'}">
+    {#if index === 1}
+      <Add16 />
+    {/if}
+    {item.label}
+  </span>
+  {#if selectedIndex === 0}Tab content {id} {index}{/if}
+  {#if selectedIndex === 1}Tab content {id} {index}{/if}
+  {#if selectedIndex === 2}Tab content {id} {index}{/if}
+  {#if selectedIndex === 3}Tab content {id} {index}{/if}
+  {#if selectedIndex === 4}Tab content {id} {index}{/if}
+</TabsV2>
diff --git a/src/Tabs/TabsV2.svelte b/src/Tabs/TabsV2.svelte
new file mode 100644
index 00000000..65ae57b1
--- /dev/null
+++ b/src/Tabs/TabsV2.svelte
@@ -0,0 +1,178 @@
+<script>
+  /**
+   * @typedef {number | string} TabsV2ItemId
+   * @typedef {{ id: TabsV2ItemId; label?: string; disabled?: boolean; }} TabsV2Item
+   * @event {{ selectedIndex: number; selectedId: TabsV2ItemId; currentItem: TabsV2Item }} change
+   * @slot {{ id: TabsV2ItemId; index: number; item: TabsV2Item; }}
+   */
+
+  /**
+   * Provide the tab items
+   * @type {TabsV2Item[]}
+   */
+  export let items = [];
+
+  /** Specify the selected tab index */
+  export let selectedIndex = 0;
+
+  /**
+   * Specify the selected tab id
+   * @type {TabsV2ItemId}
+   */
+  export let selectedId = undefined;
+
+  /**
+   * Specify the type of tabs
+   * @type {"default" | "container"}
+   */
+  export let type = "default";
+
+  /**
+   * Specify the ARIA label for the chevron icon
+   * @type {string}
+   */
+  export let iconDescription = "Show menu options";
+
+  /** Specify the tab trigger href attribute */
+  export let triggerHref = "#";
+
+  import { createEventDispatcher, afterUpdate } from "svelte";
+  import ChevronDownGlyph from "carbon-icons-svelte/lib/ChevronDownGlyph/ChevronDownGlyph.svelte";
+
+  const dispatch = createEventDispatcher();
+
+  let dropdownHidden = true;
+  let prevSelectedIndex = -1;
+
+  $: itemIds = items.map((item) => item.id);
+  $: if (items[selectedIndex] === undefined) {
+    // if the items array shrinks, `selectedIndex` could be greater than the number of items
+    selectedIndex = items.length - 1;
+  }
+  $: currentItem = items[selectedIndex];
+  $: selectedId = currentItem.id;
+
+  afterUpdate(() => {
+    if (currentItem.id !== selectedId) {
+      selectedIndex = itemIds.indexOf(selectedId);
+    }
+
+    if (prevSelectedIndex !== selectedIndex) {
+      // only dispatch the "change" event when the current item changes
+      dispatch("change", { selectedIndex, selectedId, currentItem });
+      prevSelectedIndex = selectedIndex;
+    }
+  });
+
+  function changeIndex(direction) {
+    let index = selectedIndex + direction;
+
+    if (index < 0) {
+      index = items.length - 1;
+    } else if (index >= items.length) {
+      index = 0;
+    }
+
+    let disabled = items[index].disabled;
+
+    while (disabled) {
+      index = index + direction;
+
+      if (index < 0) {
+        index = items.length - 1;
+      } else if (index >= items.length) {
+        index = 0;
+      }
+
+      disabled = items[index].disabled;
+    }
+
+    selectedIndex = index;
+  }
+</script>
+
+<div
+  role="navigation"
+  class:bx--tabs="{true}"
+  class:bx--tabs--container="{type === 'container'}"
+  {...$$restProps}
+>
+  <div
+    role="listbox"
+    tabindex="0"
+    class:bx--tabs-trigger="{true}"
+    aria-label="{$$props['aria-label'] || 'listbox'}"
+    on:click="{() => {
+      dropdownHidden = !dropdownHidden;
+    }}"
+    on:keydown="{() => {
+      dropdownHidden = !dropdownHidden;
+    }}"
+  >
+    <a
+      tabindex="-1"
+      class:bx--tabs-trigger-text="{true}"
+      href="{triggerHref}"
+      on:click="{() => {
+        dropdownHidden = !dropdownHidden;
+      }}"
+    >
+      {#if currentItem}{currentItem.label}{/if}
+    </a>
+    <ChevronDownGlyph aria-hidden="true" title="{iconDescription}" />
+  </div>
+  <ul
+    role="tablist"
+    class:bx--tabs__nav="{true}"
+    class:bx--tabs__nav--hidden="{dropdownHidden}"
+  >
+    {#each items as item, i (item.id)}
+      <li
+        tabindex="-1"
+        role="presentation"
+        class:bx--tabs__nav-item="{true}"
+        class:bx--tabs__nav-item--disabled="{item.disabled}"
+        class:bx--tabs__nav-item--selected="{item.id === currentItem.id}"
+        {...$$restProps}
+        on:click|preventDefault="{() => {
+          if (!item.disabled) selectedIndex = i;
+          dropdownHidden = true;
+        }}"
+        on:keydown="{({ key }) => {
+          if (item.disabled || !dropdownHidden) return;
+          console.log(key);
+          if (key === 'ArrowRight') {
+            changeIndex(1);
+          } else if (key === 'ArrowLeft') {
+            changeIndex(-1);
+          }
+        }}"
+      >
+        <a
+          role="tab"
+          tabindex="{item.disabled ? '-1' : item.tabindex || '0'}"
+          aria-selected="{item.id === currentItem.id}"
+          aria-disabled="{item.disabled}"
+          id="{item.id}"
+          href="{item.href || '#'}"
+          class:bx--tabs__nav-link="{true}"
+        >
+          <slot name="tab">{item.label}</slot>
+        </a>
+      </li>
+    {/each}
+  </ul>
+</div>
+
+{#each items as item, i (item.id)}
+  <div
+    role="tabpanel"
+    aria-labelledby="{item.id}"
+    aria-hidden="{item.id !== currentItem.id}"
+    hidden="{item.id === currentItem.id ? undefined : 'true'}"
+    id="tabpanel-{item.id}"
+    class:bx--tab-content="{true}"
+  >
+    <slot id="{item.id}" index="{i}" item="{item}" />
+  </div>
+{/each}
diff --git a/src/Tabs/index.js b/src/Tabs/index.js
index 34945487..c3b6e012 100644
--- a/src/Tabs/index.js
+++ b/src/Tabs/index.js
@@ -2,3 +2,4 @@ export { default as Tabs } from "./Tabs.svelte";
 export { default as Tab } from "./Tab.svelte";
 export { default as TabContent } from "./TabContent.svelte";
 export { default as TabsSkeleton } from "./TabsSkeleton.svelte";
+export { default as TabsV2 } from "./TabsV2.svelte";
diff --git a/src/index.js b/src/index.js
index 522bc154..4f433691 100644
--- a/src/index.js
+++ b/src/index.js
@@ -96,7 +96,7 @@ export {
   StructuredListRow,
   StructuredListInput,
 } from "./StructuredList";
-export { Tabs, Tab, TabContent, TabsSkeleton } from "./Tabs";
+export { Tabs, Tab, TabContent, TabsSkeleton, TabsV2 } from "./Tabs";
 export { Tag, TagSkeleton } from "./Tag";
 export { TextArea, TextAreaSkeleton } from "./TextArea";
 export { TextInput, TextInputSkeleton, PasswordInput } from "./TextInput";
diff --git a/types/Tabs/TabsV2.d.ts b/types/Tabs/TabsV2.d.ts
new file mode 100644
index 00000000..47df3f06
--- /dev/null
+++ b/types/Tabs/TabsV2.d.ts
@@ -0,0 +1,60 @@
+/// <reference types="svelte" />
+
+export type TabsV2ItemId = number | string;
+
+export interface TabsV2Item {
+  id: TabsV2ItemId;
+  label?: string;
+  disabled?: boolean;
+}
+
+export interface TabsV2Props extends svelte.JSX.HTMLAttributes<HTMLElementTagNameMap["div"]> {
+  /**
+   * Provide the tab items
+   * @default []
+   */
+  items?: TabsV2Item[];
+
+  /**
+   * Specify the selected tab index
+   * @default 0
+   */
+  selectedIndex?: number;
+
+  /**
+   * Specify the selected tab id
+   */
+  selectedId?: TabsV2ItemId;
+
+  /**
+   * Specify the type of tabs
+   * @default "default"
+   */
+  type?: "default" | "container";
+
+  /**
+   * Specify the ARIA label for the chevron icon
+   * @default "Show menu options"
+   */
+  iconDescription?: string;
+
+  /**
+   * Specify the tab trigger href attribute
+   * @default "#"
+   */
+  triggerHref?: string;
+}
+
+export default class TabsV2 {
+  $$prop_def: TabsV2Props;
+  $$slot_def: {
+    default: { id: TabsV2ItemId; index: number; item: TabsV2Item };
+    tab: {};
+  };
+
+  $on(
+    eventname: "change",
+    cb: (event: CustomEvent<{ selectedIndex: number; selectedId: TabsV2ItemId; currentItem: TabsV2Item }>) => void
+  ): () => void;
+  $on(eventname: string, cb: (event: Event) => void): () => void;
+}
diff --git a/types/index.d.ts b/types/index.d.ts
index c1862c40..4f85c41d 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -110,6 +110,7 @@ export { default as Tabs } from "./Tabs/Tabs";
 export { default as Tab } from "./Tabs/Tab";
 export { default as TabContent } from "./Tabs/TabContent";
 export { default as TabsSkeleton } from "./Tabs/TabsSkeleton";
+export { default as TabsV2 } from "./Tabs/TabsV2";
 export { default as TagSkeleton } from "./Tag/TagSkeleton";
 export { default as Tag } from "./Tag/Tag";
 export { default as TextArea } from "./TextArea/TextArea";