From 8473589e3a7d8f014d5ae2781fa53ac1f75b0a62 Mon Sep 17 00:00:00 2001
From: Eric Liu <ericyl.us@gmail.com>
Date: Wed, 22 Jul 2020 18:14:08 -0700
Subject: [PATCH] feat: add PaginationNav component

---
 src/PaginationNav/PaginationItem.svelte      |  18 +++
 src/PaginationNav/PaginationNav.Story.svelte |  31 +++++
 src/PaginationNav/PaginationNav.stories.js   |  17 +++
 src/PaginationNav/PaginationNav.svelte       | 129 +++++++++++++++++++
 src/PaginationNav/PaginationOverflow.svelte  |  47 +++++++
 src/PaginationNav/index.js                   |   1 +
 src/index.js                                 |   1 +
 7 files changed, 244 insertions(+)
 create mode 100644 src/PaginationNav/PaginationItem.svelte
 create mode 100644 src/PaginationNav/PaginationNav.Story.svelte
 create mode 100644 src/PaginationNav/PaginationNav.stories.js
 create mode 100644 src/PaginationNav/PaginationNav.svelte
 create mode 100644 src/PaginationNav/PaginationOverflow.svelte
 create mode 100644 src/PaginationNav/index.js

diff --git a/src/PaginationNav/PaginationItem.svelte b/src/PaginationNav/PaginationItem.svelte
new file mode 100644
index 00000000..9463440d
--- /dev/null
+++ b/src/PaginationNav/PaginationItem.svelte
@@ -0,0 +1,18 @@
+<script>
+  export let page = 0;
+  export let active = false;
+</script>
+
+<li class:bx--pagination-nav__list-item={true}>
+  <button
+    data-page={page}
+    aria-current={active ? 'page' : undefined}
+    class:bx--pagination-nav__page={true}
+    class:bx--pagination-nav__page--active={active}
+    on:click>
+    <span class:bx--pagination-nav__accessibility-label={true}>
+      <slot />
+    </span>
+    {page}
+  </button>
+</li>
diff --git a/src/PaginationNav/PaginationNav.Story.svelte b/src/PaginationNav/PaginationNav.Story.svelte
new file mode 100644
index 00000000..e5a034a4
--- /dev/null
+++ b/src/PaginationNav/PaginationNav.Story.svelte
@@ -0,0 +1,31 @@
+<script>
+  export let page = 0;
+
+  import PaginationNav from "./PaginationNav.svelte";
+  import { Button } from "../Button";
+</script>
+
+<div style="width: 800px;">
+  <PaginationNav
+    {...$$props}
+    bind:page
+    on:change={({ detail }) => {
+      console.log('on:change', detail);
+    }}
+    on:click:button--previous={({ detail }) => {
+      console.log('button--previous', detail);
+    }}
+    on:click:button--next={({ detail }) => {
+      console.log('button--next', detail);
+    }} />
+  <div style="margin-top: 1.5rem">Bound page index: {page}</div>
+  <Button
+    kind="tertiary"
+    size="small"
+    style="margin-top: 1rem;"
+    on:click={() => {
+      page = 3;
+    }}>
+    Set page to index 3
+  </Button>
+</div>
diff --git a/src/PaginationNav/PaginationNav.stories.js b/src/PaginationNav/PaginationNav.stories.js
new file mode 100644
index 00000000..3078e824
--- /dev/null
+++ b/src/PaginationNav/PaginationNav.stories.js
@@ -0,0 +1,17 @@
+import { withKnobs, number, boolean } from "@storybook/addon-knobs";
+import Component from "./PaginationNav.Story.svelte";
+
+export default { title: "PaginationNav", decorators: [withKnobs] };
+
+export const Default = () => ({
+  Component,
+  props: {
+    page: number("Current page index (page)", 0),
+    total: number("Total number of items (total)", 10),
+    shown: number("Number of items to be shown (minimum 4) (shown)", 10),
+    loop: boolean(
+      "Allow user to loop through the items when reaching first / last (loop)",
+      false
+    ),
+  },
+});
diff --git a/src/PaginationNav/PaginationNav.svelte b/src/PaginationNav/PaginationNav.svelte
new file mode 100644
index 00000000..9c0e8eb0
--- /dev/null
+++ b/src/PaginationNav/PaginationNav.svelte
@@ -0,0 +1,129 @@
+<script>
+  export let page = 0;
+  export let total = 10;
+  export let shown = 10;
+  export let loop = false;
+  export let forwardText = "Next page";
+  export let backwardText = "Previous page";
+
+  import { afterUpdate, createEventDispatcher } from "svelte";
+  import CaretLeft16 from "carbon-icons-svelte/lib/CaretLeft16";
+  import CaretRight16 from "carbon-icons-svelte/lib/CaretRight16";
+  import PaginationItem from "./PaginationItem.svelte";
+  import PaginationOverflow from "./PaginationOverflow.svelte";
+  import { Button } from "../Button";
+
+  const dispatch = createEventDispatcher();
+  const MIN = 4; // minimum items shown
+
+  afterUpdate(() => {
+    dispatch("change", { page });
+  });
+
+  let front = 0;
+  let back = 0;
+
+  $: fit = shown >= MIN ? shown : MIN;
+  $: startOffset = fit <= MIN && page > 1 ? 0 : 1;
+  $: if (fit >= total) {
+    front = 0;
+    back = 0;
+  }
+  $: if (fit < total) {
+    const split = Math.ceil(fit / 2) - 1;
+
+    front = page - split + 1;
+    back = total - page - (fit - split) + 1;
+
+    if (front <= 1) {
+      back -= front <= 0 ? Math.abs(front) + 1 : 0;
+      front = 0;
+    }
+
+    if (back <= 1) {
+      front -= back <= 0 ? Math.abs(back) + 1 : 0;
+      back = 0;
+    }
+  }
+  $: items = Array.from({ length: total })
+    .map((e, i) => i)
+    .slice(startOffset + front, (back + 1) * -1);
+</script>
+
+<nav aria-label="pagination" class:bx--pagination-nav={true} {...$$restProps}>
+  <ul class:bx--pagination-nav__list={true}>
+    <li class:bx--pagination-nav__list-item={true}>
+      <Button
+        hasIconOnly
+        kind="ghost"
+        tooltipAlignment="center"
+        tooltipPosition="bottom"
+        iconDescription={backwardText}
+        disabled={!loop && page === 0}
+        icon={CaretLeft16}
+        on:click={() => {
+          if (page - 1 < 0) {
+            if (loop) page = total - 1;
+          } else {
+            page--;
+          }
+          dispatch('click:button--previous', { page });
+        }} />
+    </li>
+    {#if fit > MIN || (fit <= MIN && page <= 1)}
+      <PaginationItem page={1} active={page === 0} on:click={() => (page = 0)}>
+        {page === 0 ? 'Active, Page' : 'Page'}
+      </PaginationItem>
+    {/if}
+    <PaginationOverflow
+      fromIndex={startOffset}
+      count={front}
+      on:select={({ detail }) => (page = detail.index)} />
+    {#each items as item}
+      <PaginationItem
+        page={item + 1}
+        active={page === item}
+        on:click={() => (page = item)}>
+        {page === item ? 'Active, Page' : 'Page'}
+      </PaginationItem>
+    {/each}
+    <PaginationOverflow
+      fromIndex={total - back - 1}
+      count={back}
+      on:select={({ detail }) => {
+        page = detail.index;
+      }} />
+    {#if total > 1}
+      <PaginationItem
+        page={total}
+        active={page === total - 1}
+        on:click={() => (page = total - 1)}>
+        {page === total - 1 ? 'Active, Page' : 'Page'}
+      </PaginationItem>
+    {/if}
+    <li class:bx--pagination-nav__list-item={true}>
+      <Button
+        hasIconOnly
+        kind="ghost"
+        tooltipAlignment="center"
+        tooltipPosition="bottom"
+        iconDescription={forwardText}
+        disabled={!loop && page === total - 1}
+        icon={CaretRight16}
+        on:click={() => {
+          if (page + 1 >= total) {
+            if (loop) page = 0;
+          } else {
+            page++;
+          }
+          dispatch('click:button--next', { page });
+        }} />
+    </li>
+  </ul>
+  <div
+    aria-live="polite"
+    aria-atomic="true"
+    class:bx--pagination-nav__accessibility-label={true}>
+    Page {page + 1} of {total}
+  </div>
+</nav>
diff --git a/src/PaginationNav/PaginationOverflow.svelte b/src/PaginationNav/PaginationOverflow.svelte
new file mode 100644
index 00000000..97f59323
--- /dev/null
+++ b/src/PaginationNav/PaginationOverflow.svelte
@@ -0,0 +1,47 @@
+<script>
+  export let fromIndex = 0;
+  export let count = 0;
+
+  import { createEventDispatcher } from "svelte";
+  import OverflowMenuHorizontal16 from "carbon-icons-svelte/lib/OverflowMenuHorizontal16";
+  import PaginationItem from "./PaginationItem.svelte";
+
+  const dispatch = createEventDispatcher();
+
+  let value = "";
+</script>
+
+{#if count > 1}
+  <li class:bx--pagination-nav__list-item={true}>
+    <div class:bx--pagination-nav__select={true}>
+      <!-- svelte-ignore a11y-no-onchange -->
+      <select
+        aria-label="Select Page number"
+        {value}
+        class:bx--pagination-nav__page={true}
+        class:bx--pagination-nav__page--select={true}
+        on:change={({ target }) => {
+          value = '';
+          dispatch('select', { index: Number(target.value) });
+        }}>
+        <option value="" hidden />
+        {#each Array.from({ length: count }, (_, i) => i) as i}
+          <option value={fromIndex + i} data-page={fromIndex + i + 1}>
+            {fromIndex + i + 1}
+          </option>
+        {/each}
+      </select>
+      <div class:bx--pagination-nav__select-icon-wrapper={true}>
+        <OverflowMenuHorizontal16 class="bx--pagination-nav__select-icon" />
+      </div>
+    </div>
+  </li>
+{:else if count === 1}
+  <PaginationItem
+    page={fromIndex + 1}
+    on:click={() => {
+      dispatch('select', { index: fromIndex });
+    }}>
+    Page
+  </PaginationItem>
+{/if}
diff --git a/src/PaginationNav/index.js b/src/PaginationNav/index.js
new file mode 100644
index 00000000..2e72aacf
--- /dev/null
+++ b/src/PaginationNav/index.js
@@ -0,0 +1 @@
+export { default as PaginationNav } from "./PaginationNav.svelte";
diff --git a/src/index.js b/src/index.js
index ff7e94a8..aa036dfe 100644
--- a/src/index.js
+++ b/src/index.js
@@ -64,6 +64,7 @@ export { NumberInput, NumberInputSkeleton } from "./NumberInput";
 export { OrderedList } from "./OrderedList";
 export { OverflowMenu, OverflowMenuItem } from "./OverflowMenu";
 export { Pagination, PaginationSkeleton } from "./Pagination";
+export { PaginationNav } from "./PaginationNav";
 export {
   ProgressIndicator,
   ProgressIndicatorSkeleton,