feat(component): add MultiSelect

Closes #19

src/components/MultiSelect/MultiSelect.svelte

@@ -0,0 +1,294 @@
+<script>
+  let className = undefined;
+  export { className as class };
+  export let id = Math.random();
+  export let titleText = '';
+  export let helperText = '';
+  export let disabled = false;
+  export let value = '';
+  export let open = false;
+  export let selectedIds = [];
+  export let items = [];
+  export let itemToString = item => item.text || item.id;
+  export let placeholder = '';
+  export let filterable = false;
+  export let invalid = false;
+  export let invalidText = '';
+  export let translateWithId = undefined;
+  export let size = undefined;
+  export let type = 'default';
+  export let locale = 'en';
+  export let sortItem = (a, b) => a.text.localeCompare(b.text, locale, { numeric: true });
+  export let filterItem = (item, value) => item.text.toLowerCase().includes(value.toLowerCase());
+  export let label = '';
+  export let useTitleInItem = false;
+  export let selectionFeedback = 'top-after-reopen';
+  export let light = false;
+  export let style = undefined;
+
+  import { afterUpdate, setContext } from 'svelte';
+  import WarningFilled16 from 'carbon-icons-svelte/lib/WarningFilled16';
+  import { cx } from '../../lib';
+  import Checkbox from '../Checkbox';
+  import ListBox, {
+    ListBoxField,
+    ListBoxMenu,
+    ListBoxMenuIcon,
+    ListBoxMenuItem,
+    ListBoxSelection
+  } from '../ListBox';
+
+  let multiSelectRef = undefined;
+  let fieldRef = undefined;
+  let selectionRef = undefined;
+  let inputRef = undefined;
+  let inputValue = '';
+  let initialSorted = false;
+  let highlightedIndex = -1;
+  let prevChecked = [];
+
+  setContext('MultiSelect', {
+    declareRef: ({ key, ref }) => {
+      switch (key) {
+        case 'field':
+          fieldRef = ref;
+          break;
+        case 'selection':
+          selectionRef = ref;
+          break;
+      }
+    }
+  });
+
+  function change(direction) {
+    let index = highlightedIndex + direction;
+
+    if (index < 0) {
+      index = items.length - 1;
+    } else if (index >= items.length) {
+      index = 0;
+    }
+
+    highlightedIndex = index;
+  }
+
+  function sort() {
+    return [
+      ...(checked.length > 1 ? checked.sort(sortItem) : checked),
+      ...unchecked.sort(sortItem)
+    ];
+  }
+
+  afterUpdate(() => {
+    if (checked.length !== prevChecked.length) {
+      if (selectionFeedback === 'top') {
+        sortedItems = sort();
+      }
+      prevChecked = checked;
+      selectedIds = checked.map(({ id }) => id);
+    }
+
+    if (!open) {
+      if (!initialSorted || selectionFeedback !== 'fixed') {
+        sortedItems = sort();
+        initialSorted = true;
+      }
+
+      highlightedIndex = -1;
+      inputValue = '';
+    }
+
+    items = sortedItems;
+  });
+
+  $: menuId = `menu-${id}`;
+  $: inline = type === 'inline';
+  $: ariaLabel = $$props['aria-label'] || 'Choose an item';
+  $: sortedItems = items.map(item => ({ ...item, checked: selectedIds.includes(item.id) }));
+  $: checked = sortedItems.filter(({ checked }) => checked);
+  $: unchecked = sortedItems.filter(({ checked }) => !checked);
+  $: filteredItems = sortedItems.filter(item => filterItem(item, value));
+  $: highlightedId = sortedItems[highlightedIndex] ? sortedItems[highlightedIndex].id : undefined;
+  $: value = inputValue;
+</script>
+
+<svelte:body
+  on:click={({ target }) => {
+    if (open && multiSelectRef && !multiSelectRef.contains(target)) {
+      open = false;
+    }
+  }} />
+
+<div
+  bind:this={multiSelectRef}
+  class={cx('--multi-select__wrapper', '--list-box__wrapper', inline && '--multi-select__wrapper--inline', inline && '--list-box__wrapper--inline', inline && invalid && '--multi-select__wrapper--inline--invalid', inline && invalid && '--list-box__wrapper--inline--invalid', className)}
+  {style}>
+  {#if titleText}
+    <label class={cx('--label', disabled && '--label--disabled')} for={id}>{titleText}</label>
+  {/if}
+  {#if !inline && helperText}
+    <div class={cx('--form__helper-text', disabled && '--form__helper-text--disabled')}>
+      {helperText}
+    </div>
+  {/if}
+  <ListBox
+    aria-label={ariaLabel}
+    class={cx('--multi-select', filterable && '--combo-box', filterable && '--multi-select--filterable', invalid && '--multi-select--invalid', inline && '--multi-select--inline', checked.length > 0 && '--multi-select--selected')}
+    {id}
+    {disabled}
+    {invalid}
+    {invalidText}
+    {open}
+    {light}
+    {size}>
+    {#if invalid}
+      <WarningFilled16 class={cx('--list-box__invalid-icon')} />
+    {/if}
+    <ListBoxField
+      role="button"
+      tabindex="0"
+      aria-expanded={open}
+      on:click={() => {
+        if (filterable) {
+          open = true;
+          inputRef.focus();
+        } else {
+          open = !open;
+        }
+      }}
+      on:keydown={({ key }) => {
+        if (filterable) {
+          return;
+        }
+        if (key === ' ') {
+          open = !open;
+        } else if (key === 'Tab') {
+          if (selectionRef && checked.length > 0) {
+            selectionRef.focus();
+          } else {
+            open = false;
+            fieldRef.blur();
+          }
+        } else if (key === 'ArrowDown') {
+          change(1);
+        } else if (key === 'ArrowUp') {
+          change(-1);
+        } else if (key === 'Enter') {
+          if (highlightedIndex > -1) {
+            sortedItems[highlightedIndex].checked = !sortedItems[highlightedIndex].checked;
+          }
+        }
+      }}
+      on:blur={({ relatedTarget }) => {
+        if (relatedTarget && relatedTarget.getAttribute('role') !== 'button') {
+          fieldRef.focus();
+        }
+      }}
+      {id}
+      {disabled}
+      {translateWithId}>
+      {#if checked.length > 0}
+        <ListBoxSelection
+          selectionCount={checked.length}
+          on:clear={() => {
+            sortedItems = sortedItems.map(item => ({ ...item, checked: false }));
+            fieldRef.blur();
+          }}
+          {translateWithId}
+          {disabled} />
+      {/if}
+      {#if filterable}
+        <input
+          bind:this={inputRef}
+          role="combobox"
+          tabindex="0"
+          autocomplete="off"
+          aria-autocomplete="list"
+          aria-expanded={open}
+          aria-activedescendant={highlightedId}
+          aria-disabled={disabled}
+          aria-controls={menuId}
+          class={cx('--text-input', inputValue === '' && '--text-input--empty')}
+          on:input={({ target }) => {
+            inputValue = target.value;
+          }}
+          on:keydown
+          on:keydown|stopPropagation={({ key }) => {
+            if (key === 'Enter') {
+              if (highlightedIndex > -1) {
+                sortedItems[highlightedIndex].checked = !sortedItems[highlightedIndex].checked;
+              }
+            } else if (key === 'Tab') {
+              open = false;
+            } else if (key === 'ArrowDown') {
+              change(1);
+            } else if (key === 'ArrowUp') {
+              change(-1);
+            }
+          }}
+          on:focus
+          on:blur
+          on:blur={({ relatedTarget }) => {
+            if (relatedTarget && relatedTarget.getAttribute('role') !== 'button') {
+              inputRef.focus();
+            }
+          }}
+          {disabled}
+          {placeholder}
+          {id}
+          value={inputValue} />
+        {#if invalid}
+          <WarningFilled16 class={cx('--list-box__invalid-icon')} />
+        {/if}
+        {#if inputValue}
+          <ListBoxSelection
+            on:clear={() => {
+              inputValue = '';
+              open = false;
+            }}
+            {translateWithId}
+            {disabled}
+            {open} />
+        {/if}
+        <ListBoxMenuIcon
+          on:click={() => {
+            open = !open;
+          }}
+          {translateWithId}
+          {open} />
+      {/if}
+      {#if !filterable}
+        <span class={cx('--list-box__label')}>{label}</span>
+        <ListBoxMenuIcon {open} {translateWithId} />
+      {/if}
+    </ListBoxField>
+    {#if open}
+      <ListBoxMenu aria-label={ariaLabel} {id}>
+        {#each filterable ? filteredItems : sortedItems as item, i (item.id || i)}
+          <ListBoxMenuItem
+            active={item.checked}
+            highlighted={highlightedIndex === i}
+            on:click={() => {
+              sortedItems = sortedItems.map(_ =>
+                _.id === item.id ? { ..._, checked: !_.checked } : _
+              );
+              fieldRef.focus();
+            }}
+            on:mouseenter={() => {
+              highlightedIndex = i;
+            }}>
+            <Checkbox
+              readonly
+              tabindex="-1"
+              id={`checkbox-${item.id}`}
+              title={useTitleInItem ? itemToString(item) : undefined}
+              name={itemToString(item)}
+              labelText={itemToString(item)}
+              checked={item.checked}
+              {disabled} />
+          </ListBoxMenuItem>
+        {/each}
+      </ListBoxMenu>
+    {/if}
+  </ListBox>
+</div>